As someone further up surmised, this is probably a B&G bolt conversion. (see the UT archives for more details) While these bolts were slightly crude due to their inherent manufacturing constraints, they tend to be very reliable. They also suffer aesthetically because of the slot milled through the front. This also makes them lighter, read FASTER, not really a positive for SOME shooters. (Like me)
The pluses here are several. First and foremost you have an IMI receiver. Sorry, but the Vector Minis are still cut down Full size Group receivers. For every owner who's happy, you'll find two more with issues. In Vector's defense, they can USUALLY get them to run. Resale value will ALWAYS be higher for IMI. If you don't believe that, you only need to spend some more time on GB.
The Reg bolt will also allow you to use it in a Pistol receiver. (You'll have to make some minor mods to it) You can even put it back in a Full size Uzi if you really want to.
Bottom line: If you really want a Mini Uzi, this is a good price for a B&G bolt gun in an IMI host gun. I paid more than the "Buy Now" price for mine and don't regret it one bit.
Judging from the bidding, I'm not the only one who feels that way. I'll be surprised if it doesn't sell. If he had listed it on Tom's or Buddy's board, it'd be gone by now.
Jack007