I think your looking at year 1981, but not positive. I have one of each, blue and nickel, both "K" series which date to 1980. The "LA" series came after the "K".
I hate to comment on prices with the way the market is, but I wouldn't pay more than $1000 for 98%. NIB around $1300. Once again, people are asking unreasonable prices. This is one to watch and wait for because they pop up every so often. Not the most rare Colt. I have no idea how many were actually made.
Guess I might have been wrong all along about the "K" series coming before the "AL" and "LA". Were these maybe produced at the same time on different production lines? Whereas, a "K" series and an "LA" series could have completed production on the same day (theoretically)?
Where is the s/n data from 1978 to 1985 documented? I thought someone once said it was in one of the books.