Nice score!
It pays to be vigilant. As for getting the set to work it is more likely a matter of when than if; that's pretty forgiving gear. The dented can, once straightened, should be serviceable, although one of the variable capacitors may need some TLC and tweaking.
My guess is that whoever threw that equipment so unceremoniously into the dumpster didn't know a coil from a boil. A few years ago I scored a National NC303 at a local scrap yard. Fortunately it was set carefully just off to the side of the "tin pile", and had had nothing heavy land on it yet when I grabbed it, so it's all straight and complete. Some day I'll get up the ambition to recap it and fire it up.
At any rate I can imagine your dumpster dive being risky to life and limb; that unit you snagged looks very heavy indeed.