Wayne, you may have something with the NPM Stock to Winchester. My 5.6 Winchester and another in BQ's term "Mirror Image" in the data base is what makes the AU recoil plates legit. Underwood sent 500 Recoil plates to Winchester in Nov of 43 and by March 44 they got around to using them. That would be a great connection.
The rebuild to type 2 sights almost always was accompanied by a new front sight. My NPM has an RIA front sight. It makes those carbines shoot dead on where an existing sight might be filed down to make it work with a flip sight.
The $2K price is some guy doing a shoot for the moon deal. I'd meet him in person and have the $1600 in cash in hand and appeal to his better sense and the value of taking care of friends. Then point out the pitfalls of dealing with the shipping, insurance FFLs, the possibility of fraud at the other end, possible rejection and associated fees etc. I'd also tell him about the consensus of opinion from this board and then just let it go. Karma has a way of working things out the way they are supposed to work. Tell him about the spring tube carbine's history of failing from cracks and how Winchester had to change to a better way on the rest of their carbines. This is just an honest example of 1 of 6.5M made, nothing special or uber exciting. Good luck.