Beeman, according to his catalogues that M.A.G. provided, supplied after market parts to modify the standard FWB Sport plus other rifles (HW35/80 etc.). The rifle I own has a Beeman walnut stock, back sight plate etc. .
With regards to the mounts. When I removed the scope from the rifle using the Q.D. mounts, which takes just a few seconds, on replacing the scope the point of aim only varies slightly. (1/4" @ 30 yds approx.)
The Exacts I use are JSB.
HTH
Ian