I really don't see how the little mount screws (that can strip, and break the heads off easily) could EVER protrude into a 7075-T6 aluminum body. Just don't see it.
Are there any "bits" of aluminum floating around inside the unit? There would be if this be the case.
I just looked inside one of my Sig Romeo 5's (I know it's not the same, but still) and see a hole that protrudes inside the tube from the factory. It's offset and doesn't align with a mount screw. Also, at the back close to the emitter there is a fairly large hole as well.
No way the Romeo 5 is purged.
Just curious OP. I'm not saying the the dude you bought it from didn't "screw it up" somehow, but I'll be damned if I believe those little mount screws could ever breech the housing before snapping the head off...
ETA: I'd call Aimpoint CS if ask them the same question. Could a mount screw ever breech the tube if over-torqued?
ETA II: Just looked inside my brand spank'n newly procured Holosun HE515GT-RD. It too has a small hole inside the tube towards the front (in a different spot compared to the Sig,) and a large hole in the back around the emitter.) Again, no way is this purged either.