I recently came across more evidence of county marked arms in Colonial Virginia. The revised Virginia militia regulations passed in 1755 stipulated that in case any militia man was too poor to afford his own arms each county was “to depute some person to send for the same [arms] to England…which arms so to be sent for shall be marked with the name of the county (Henings’ Statutes 29 August, 1755 volume 6 page 532). A surviving musket marked Hanover County survives in a private collection and a 1776 Va Gazette ad mentions another gun marked to Dinwiddie county in 1775: http://research.history.org/DigitalLibrary/VirginiaGazette/VGImagePopup.cfm?ID=4599&Res=HI
That being said, I stumbled upon a much earlier reference to the practice in the Virginia Gazette with a bit of a financial scandal involved to boot:
THE VIRGINIA GAZETTE April 22, 1737
I receiv'd the following Letter from Col . Conway, soon after the Death of Sir John Randolph; and deserr'd the Publication of it, till I heard further from him, believing the whole Affair wou'd then have ceas'd, and knowing that Col . Spotswood had declin'd publishing several Remarks on Sir John's last Letter, when he was inform'd Sir John lay dangerously ill. But Col . Conway thinking it necessary to vindicate himself, in his Proceedings, as a Member of the Assembly, from the Complaints of Col . Spotswood, to the World, desires it may be publish'd; and therefore I give it a Place in my Paper .
Mr. Parks ,
I desire you to publish in your next Paper, the following Narrative, and you will oblige,
Sir, Your humble Servant,
A HINT to discover a few of Col . Spotswood's Proceedings .
COL. Spotswood was Governor of Virginia about Twelve Years; in which Time, he summon'd Five several Assemblies, which held Ten Sessions: The First met in October 1710, which he dissolved on a sudden, in 1711, to prevent the Burgesses Vindication appearing on their Journal, against his Speech of the 28th of January ; wherein he accused them of Injustice, Ignorance, and Obstinacy: A Committee, by Order of the House, considered his Speech, and their Clerk took Memorandums of their Answer to each Paragraph, and was order'd to put'em in Form, to be reported to the House next Day; which gave Time for the Governor to hear of the Substance of their Answer; upon which he took the Advantage, and dissolved the Assembly.
Col. Spotswood , in his Answer to Sir John , says, "That immediately after passing the said Act, in 1720, he wrote to London , to provide 600 Firelocks, Bayonets, and Cartouch Boxes; the one Half to be marked with the Name of Spotsvlvania , and the other Half with that of Brunswick ." Why then were they not delivered before August 1736? He owns, that he received the Money to pay for 'em, in 1722; Is it not strange then, that the Assembly shou'd have the Trouble of so many Complaints about the Arms for Brunswick ? And is it not more strange, that he should complain to the World against the Burgesses, for Resolving that an Action shou'd be commence'd against him, for the Money he had received 14 Years before, to buy Arms for the People of Brunswick , if they be not delivered by next June ? They never demanded so much as One Penny Interest for the 14th Years Use of the Money, tho' he had been allowed to per Cent . Commission, for buying the Arms: Can he fairly pretend to justify his Delay, and claim the Honour of Governing this Colony 12 Years, with Approbation?
Can Col. Spotswood imagine, that every one has forgot how he troubled the Country, in 1711, with strange Alarms; and quarrelled with the Burgesses, and abused them, because they could not humour him; and dissolve 'em suddenly, to present their Vindication appearing on their Journal, against him?
Can he think that none remembers how he abused the Burgesses in 1715, when he encouraged several Persons to affront, and despise 'em, and dented his Assistance to the House?
Can he think none remembers the Queries he had printed, and dispers'd about the Country, to deferr the County Courts from levying the Burgesses Wages, settled by Law, as well as by the constant Custom of the Country?
Prince William county seems to have purchased both muskets and pistols in 1759, in 1760 Governor Fauquier communicated to the council that" many stands of arms had lately been imported for the militia of King and Queen, Gloucester, and James City counties." when Virginia found herself short of arms yet again for the Cherokee campaign under Byrd. Richard Corbin wrote Capel and Osgood Hanbury Esq about the purchase for King and Queen county, "In march 1757 I wrote to you for 100 stands of arms for King & Queen county and desired them to be insured..." (M-1560, Corbin Papers letterbook 1758-68 Colonial Williamsburg MS collection).
Hopefully more references and originals will turn up!