You may be in luck: I see none of the marks for an enlarged chamber. If you have a really nice bore, you have something very shootable, even restorable.

Typical commercial sporterization, in this case done in the UKicon. Too bad they had to slap those "NOT ENGLISH MAKE" stamps all over it.

The two fives I have never seen before and they look like they went on before the original finish.

Looks like a 5 or 6 as the last digit of the date(?)