That is an early 1807 (technically an 1807L for Left handed) unless the serial number has an X suffix, then it would be what is known as a 1607 which was a transitional model produced for a few years around that ('78-'81 or so) time.
It was made for a class of competition known as Standard Rifle which limits the weight and adjustments that can be made to the rifle during a match.
In international/olympic competition, up to the mid/late 90's, women were required to use a standard rifle.