This has happened to me twice, once at HS trading and recently at B&K. Ruger MKXXX in a bag. I put both back together for the customers. I really don't understand why people have so much trouble putting these back together. Granted there are a few step but it is not rocket science. The only tool required sometimes is a plastic hammer or a block of wood.I was in a gun shop a few years ago when someone came in with a disassembled MKll in a box, couldn't get it back together.
The salesman says no problem, let me show you. He couldn't get it either, so has a brainstorm and takes apart a brand new gun to refresh his memory.
When I left, they had the customer's gun and TWO brand new guns apart with no clue how to put them back together.
They're no longer in business.