you can drill & tap 1 of the 2, the other is not in the correct location.
passenger side US, IIRC these 2 are correct
drivers side US see where the rearward boss is out of place?
FWIW IMO $450 is not too much for a usable FMX block but the example you've found is rough, needs to be evaluated before it can be determined usable at all even with some repair. with that much rust / water damage i'd be concerned about cracking / freeze damage and excessive pitting.
$450 ? it's only money. they're out there, a couple on the FB page recently are not selling for a little more but much better condition going in