That's not strat bridge, it's one of those other shortscale guitar bridges, maybe a Bronco, not sure.
It's definitely heavily customised, the tuners clearly haven't been tightened properly as they're all a bit wonky. The headstock decal is homemade for sure, the Mustang logo just isn't right. My bet is the body is from one of the other shortscale guitars with the strings that go through the back, made to be a Mustang. They've routed it for a humbucker, that's always nice, and I prefer reverse headstocks so that's cool.
If I could afford it, I'd buy it no matter how messed up it is. 😛
