Serial numbers ran from 25K0001 in 1978 to 56K9999 in 1979.
Production ran from 1955 to 1999. The -4 was the last engineering change to still have the pinned barrel and recessed cylinder, it was deleted with the -5 series.
1980.
Depending on condition, with or without original box and accessories, value ranges from $300 to $500+.
Jim