Hi Randy - I think your overall question is quite interesting. My 1984 D-64 is pretty rare, only 193 made, according to serial number information I have. And our esteemed colleague Hans attests to it's relative rarity.
My other guitar, a 1966 Epiphone Casino ES230T (single pickup) is also relatively unique. According to vintageguitars.org, there were only 218 of this model made in 1966. Mine is a "Royal Tan" finish, which like your T-50, seems more unique than the sunburst model, but how unique I don't know. I've never been able to find out the manufacturing numbers for each particular finish.
By the way, I have played a T-50 before - those are great guitars! I love the thin-body electrics! And I agree that the blonde finish certainly appears harder to find...
walrus