Another option would be to buy a parts kit and build it yourself.
Not for an M-60, mind you... I don't think I've ever seen an M-60 parts kit for sale.
But there's still plenty of 1919 parts kits available for 450-500. You can get an 80% right side plate (the controlled part) for 80 or 100 bucks, no ffl required if 80% or less complete, and finish it on a drill press using the other pieces of the receiver box as a template. All it lacks is drilling and chamfering most of the rivet holes.
I built a semi for about 650 total a couple years ago when kits were 300 bucks. That included the semi-auto trigger and sear and machinist work on the bolt, barrel ext, and lockframe.
For display purposes, I would suggest belting up alot of dummy ammo for it AND using a dummy bolt with no firing pin or something.
Doesn't get any more realistic than the real thing. And for not much more than those replicas, you've got a real gun to fire from the truck at the local range. Uh... don't drive around in Austin with that on your truck, uncovered unless you like inspecting the pistol barrels of APD bicycle cops.
I have no idea if Ma deuce parts kits are still available, tho. I bet they're alot more expensive than 1919 kits, if they are, tho.