I don't know where the two-digit thing comes from, but I know for sure that doesn't hold to a couple of other models of CVA's traditional rifles (so I doubt its true here either).
When it was made I'm not sure, but between 1971-1991 if while CVA still sold the traditionals themselves (before selling out that business to Deer Creek). This model is not in the mid 70's or late 80's CVA catalogs.
CVA Plainsman Flintlock, .50 caliber, barrel 26", 1:48 twist.
Case-hardened lock; brass bead front, fixed rear sights, hardwood stock, 6 1/2 lbs.
MSRP $160
IMO only a couple of CVA traditional muzzy models might be called collectable, and this is not one of them.
HTH