Originally Posted by
Geezer
Welcome, Gary.
I am by a long way not an Airsporter expert.
But. Here's what I know.
The Mk1 should not have scope mount grooves.
The Mk2 does.
So have you got the mark right?
There are some so-called Mk1 and a half transitional models. Maybe you have one. They mix and match Mk1 and Mk2 features.
John Knibbs (Google "airgunspares") sells scope mounts for the Mk2.
The usual distinctions between Mk1 and Mk2 are that the former always had a 3-piece laminated stock, a tapered barrel, a non-folding rear sight and no scope mount cuts. The Mk2 usually had a folding rear sight, a one-piece stock, scope mount cuts, and a straight non-tapered barrel.
The intermediate "Mk1.5" models had a variety of the features of both.
Hope that helps. In any case, Mk1,2, and "1.5" Airsporters are good guns, and interesting and collectable.