Nice work. What can you tell us about the holster? Completely custom job? Since you're moving forward with this, I'll share some tidbits I've come up with.
Hector de la Rosa had posted an item on his site about Snake’s gun having been used in an episode of “The Greatest American Hero,” and that was very helpful in identifying the correct scope base and rings. It appears both with and without a shoulder stock, and with a Leupold scope mounted backward.
Scope mount (Leupold or Redfield) and rings. The scope base is a rifle type with a cutout (so that the mount doesn’t interfere with the loading or ejection of rounds), which leads me to believe that the suppressor was cobbled together with whatever parts happened to be laying around the shop.
scope: leaning toward Weaver classic rifle scope (Lyman Challenger looked fairly close) The scope ON THE TABLE is a Leupold. That’s all I can tell.