Yep, the whole gun was cast in resin as one piece. See Stormtrooper's thread for pics of his screen-used blaster.The E11/sterling type stormtroopery one ..
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but the paintjob seems evenly weathered , even over the rubber T track...like it was all one material .
I came to the conclusion this gun is probably a foam or rubber one piece stunt cast pressed into service as IG's, hence blocked areas ,no trigger guard /trigger and paintjob .