Yeah, there was a poor attempt by someone to weld it back to the base, so I'd have to grind all of that off.
Yeah, mine has like what look to be broken bolts in the side from a prior attempt to fix it. Fortunately, this anvil still has a nice ring across the whole top
Without all the weight and wide footprint that the base gave it, I think it would wobble all over the place, and there is nowhere to attach a chain/nail/strap to hold it to the stump.
I'm thinking bolting from the bottom to a ~1/2" plate, and then lag screwing that down to the stump. At least that way I don't have to worry about screwing up the temper of the top.