No, there's aren't any records of build dates, they were destroyed in a fire.
No one even really knows for sure how the guns were numbered because they don't all fit into a single chronological order.
There is said to be different serialization for each model and possibly for each caliber of the same model.
And that may mean that a flintlock could have different serialization than a percussion, and a .45 may have different serialization than a .50
And possibly there were different series of serial numbers depending on who made the barrels.
There's a lengthy thread on the MLF that discusses serial numbers and where a bunch of people stated their recollections of when they purchased their guns. --->>>
https://www.muzzleloadingforum.com/threads/serial-number-dating-a-t-c.34284/
Some recollections may be faulty.
There's also mention of some characteristics such as markings on the barrel, and whether there was a warning on the barrel or not.
But it's pretty much agreed to that 3 or 4 digit serial numbers are the earliest production.
The last poster in the thread stated:
"My TC Hawkin was bought new in early 1971 and is number 2069. It has a steel case hardened trigger guard and butt plate." --->>> See Page 8 Post #160 [the last post of the thread]
https://www.muzzleloadingforum.com/threads/serial-number-dating-a-t-c.34284/page-8#post-1639079
The steel trigger guard was mentioned as maybe only having been shipped with a first year model, or extremely early model.
Otherwise the Hawken trigger guards were brass.
Another poster stated:
"My 1973 Hawken 50 caliber purchased in 1974 has a serial number 8079."
And another poster stated about his Hawken flintlock:
"TC .50 cal. Hawken flintlock, serial number 5537. Bought brand new the year before Pa. started a flintlock season. I believe the season was 1976, not real sure on that but back then we had to hunt only on designated state game lands. "
Wikipedia states that the TC Hawken was designed in 1970.
"The traditional Thompson/Center muzzleloaders are largely responsible for the resurgence of black powder hunting that began in the U.S. in 1970 when Warren Center designed the firm's Hawken-styled rifle." --->>>
https://en.wikipedia.org/wiki/Thompson/Center_Arms#Muzzleloading_rifles
Out of curiosity I would like to hear more details about your guns, such as calibers and any identifying features or barrel markings.
Perhaps you can post some photos so that we could see them.
Did you buy them used or obtain them from a family member?
My best guess would be that they were made in the early 1970's.
