There were two Vincent's, father and son.
John was born in 1809 and first apprenticed as a cabinet maker and later became a farmer. He really didn't start building rifles until he was in his later 30's (age 38 by one account), which would potentially put his first rifle somewhere in the late 1840's.
John was primarily a farmer, his cabinet work was secondary with rifle building taking third place behind the other endeavors.
John Caleb was born in 1841. He also trained as a cabinet maker. His early rifles would have dated to at least the mid/late 1850's at best.
So both were building (perhaps more as a secondary source of income) during the cap lock era. Although Caleb left his father's shop to more actively pursue gunsmithing initially setting up a shop in Vincent Station in the back of a grocery store owned by his uncle. It has been estimated, based on shop records, that he probably didn't produce more than 15 rifles in any given year.
Earlier journal entries from his fathers shop show that 15 rifles were built in 1848, with only 3 and 2 in the following two years, and between 1860 and 1863 a total of 15 rifles were made - so definitely not exactly "prolific". (as a side note, only one pistol was listed as being produced between 1848 and 1863).
There is a couple of full-stock "flint" Vincent's out there that have been displayed/documented but I have never personally seen a flint half-stock (perhaps the AOLRC could be of assistance with that).
The butt plates did take on a more severe crescent shape as time went on as the entire architecture got more (sharp/severe - not sure how to describe it).
Take note particularly in the last two rifles in the picture of an early flintlock compared to a late Caleb half-stock.
All of these are Vincent's, so following any of the architecture would be "correct", you don't necessarily need the severe butt plate and high/thin comb line, even though that is usually what comes to mind when someone mentions "a Vincent".
