That case sounds like it was the theft of old antique guns that were worth alot of money....over a million. Seems that they were trying to sell them back to the insurance company.
But the guns i'm thinking of came either direct from the manufacturer or maybe a gun distributor according to Hill. All brand new guns that Hill said were right from the factory. On that 'Locked up Abroad" show on Hill, Henry said Jimmy loved them and bought all of them. But in the movie it showed Jimmy calling them garbage and refusing to buy them. Not sure if Henry's story about the guns has changed or the Goodfellas writers just changed it. With Hill you never know.
The Perla brothers were from Braddock Hills and were not connected to any mobsters. They both went to high school with Kuhn, the guy who was part of the fix.
Thanks JCB.