Colt Vipers were only made in 1977 but some serial numbers carried over until 1978-but several years later Colt produced some Vipers made up from existing parts as a clean-up...but these are even more valuable than the original Vipers...they were shipped in Colt blue plastic boxes and they had a different style of wood grips...but all Vipers in mint condition are highly collectible now...but are hard to find. I managed to collect a couple of (unfired) Vipers fairly recently...following are some photos: