Folks, here is a lot of 18th century background information that pertains to the OP’s choice of gun both directly and indirectly. Fair warning, this will be a long post. So, for those who complain about long posts, please feel free to stop now. For everyone else, I hope you will enjoy this.
Any gun here in the colonies during the 18th century before the AWI was very expensive, but not quite as expensive as some think. For example, it did not take a year’s wages for most folks to purchase a gun, rather more on the order of two to six months wages, depending on how much a person made. Now, it DID take most folks a year or more to save up the EXTRA money for a gun and that’s probably how that myth began.
For example, the following link shows what a rather high end rifle from a known Master Gunsmith cost in 1773, shortly before the AWI. It cost 8 pounds, no doubt from the added cost of the double triggers and inlaid silver.
Christian Oerter Letter (flintriflesmith.com)
On average for this period, average cost for rifles might go for as little as 5 pounds and up to around 7 pounds depending on the added features. (That’s 100 to 140 Shillings.) New Smoothbore guns often went for between 2 to 3 ½ pounds or 40 to 70 Shillings, for an average gun. The lowest wages paid was for common laborers and since meals were included in their wages, they only got 2 Shillings per week. So, it would take them 20 weeks or 5 months wages to pay for the least expensive new smoothbore. However, apprentices in the trades were paid between 4 to 6 Shillings per week, so the same gun would have taken no more than 10 week’s or 2 ½ month’s wages for them. Journeymen were paid between 10 to 14 Shillings per week, so it would only take them a month’s wages for the same gun. The rather high end Christian Oerter rifle above at 8 pounds, would have cost a Journeyman in the trades between just over 3 to 4 month’s wages and less than that for a plainer rifle. This is “sort of” comparable to what the “Average Joe” makes today.
It sometimes is difficult for us to imagine today, but in the 18th century, brass was EXPENSIVE here because virtually none was made here until small amounts during the AWI. They could get zinc from Peru to make it, but no major copper mining began until 1784, the year after the AWI was over. During the AWI, gunsmiths like the Geddy brothers in Williamsburg, VA advertised in the Virginia Gazette Newspaper for broken brass buckles, broken brass horse tack and broken candlesticks to get the scrap brass to cast into gun furniture. Up until that time, brass side plates, butt plates, trigger guards and sheet brass were made in England or the Continent and imported here. So not adding a patch box or even a butt plate were real cost saving measures IF a person couldn’t afford them or didn’t feel the need them.
Now to gun locks. An Apprentice gunsmith had to make one entire gun (either smoothbore or rifle) to successfully finish his apprenticeship. However, until the AWI, that may have been the LAST complete Lock the Gunsmith ever totally made in his entire career. Gunsmiths here could not compete with the prices of locks imported from the factory shops in England, Belgium, the Netherlands, Germany, or France. So almost every lock he used after making one for his first gun was imported. Now some gunsmith firms did set up lock making after the AWI, but many went right back to using imported locks until the 1790’s to the turn of the century when many English Lock Makers immigrated here.
Now as to the smoothbore the OP is considering. No, it is not a copy of a known gun, but it doesn’t have to be. MANY guns were assembled during the early years of the AWI with WHATEVER parts gunsmiths could lay their hands on. As long as the gun reliably and safely went BANG when the owner/user pulled the trigger, they were happy to get it. However, I would also echo some recommended changes to make it into a possible “composite” gun assembled during the early part of the AWI.
Some really cheap guns did not have side plates at all, but most had them and they were all with two side lock screws. It’s too late to go with no side plate on that gun and I concur with others who recommend a full side plate of pre AWI form be added. A surprising number of original guns had the front side lock screw heated and hammered thinner in the middle to full size at each end, to fit between the barrel and ramrod hole. Also and unlike the way many 18th century REPRO guns are drilled for full diameter rods and tips, it was common for the ramrods to be tapered in the rear end to clear the front lock bolt. Adding some kind of butt plate would also be good to keep down damage to the toe of the stock.
Gus