That's a pretty @#$$% return/refund policy. I would expect better from Bryan/the folks at AIM, but alas...it is what it is. You'll either eat the ~$30 in return charges and S&H or you'll lose it on the retail side trying to sell a .308 BCG with known QC issues. Either way...you are on the losing end of things.
I would almost guarantee you that if they have any detailed images on their site of the product in question that they look 100% clean and free from any machining marks, staking that's off, etc. If so, you might pull that card and see if anything changes their mind. Also, you might check in on their Industry forum page on BARFCOM and see if anyone else has had similar issues and if so, how they were addressed/resolved. If you are having issues, I'm betting its not the first or the only case around especially if these are rebranded 762 Industries/DRD/like products being sold by AIM.