Hey David. Asking questions on the GTA is just like Lays potato chips-- ya can't ask just one ;~D Keep 'em coming.
To follow up on Randy's reply, I think I read on Gene's Airgun Toys website that his shrouds aren't constructed in a way that would take care of the problem that you'd like to solve. They're well-crafted from what I've seen in the pics, but you might have to contact another supplier if you're interested in reduced auditory functionality.
Stupid anti-anti-noise laws! (and by that I mean Fed's rules, not the GTA's rules)
Bryan