Originally Posted by fireblade
Without having any pictures at hand, i will try and tell you the best i can
Mk1, has blued barrel and air cylinder with a gray/silver coloured breech block which has curved features, the barrel is glued to a brass transfere port tube, this part you will see when loading. Silver painted stock, butt plate and cheek piece have 2 steel rod adjusters.
Just to add detail to this but the Mk1 also came with the unpainted laminate stock, a mate has one he bought from new. Also there are two versions of the Mk1, very early ones had a heavier hammer and a different fill adapter (quick release air line type rather than the later push on or T bar types).
Iscao, the anti tamper is basically blanking screws for the hammer spring and transfer port so they cant be adjusted by the owner, AAs effort to prevent guns being tweaked to over 12ftlbs.