Alolan Golem vs. Regular Golem - Rock Throw and Rock Blast

Rock Blast will be fine on either type of Golem...especially if you prefer multi bar charge moves (I know I do).
If you need it, and it will find a place in the team, then then it will work very well for you.
I have one...and he has seen plenty of action.

Regular Golem is Rock/Ground type.
Alolan Golem is Rock/Electric type.

Regular Golem is weak to ice attacks, which Alolan Golem takes neutral damage from. This makes regular Golem more fragile against Articuno.

Regular Golem is resistant to flying attacks, but Alolan Golem is doubly resistant to. Hence regular Golem is more fragile when Moltres and Articuno have flying charged moves (Sky Attack and Hurricane respectively).

The damage per second (DPS) for Rock Throw + Stone Edge is higher than the DPS for Rock Throw + Rock Blast. Since Stone Edge is a one-bar charged move, there is a higher risk that a fragile attacker will faint before firing it off (in contrast, a three-bar move like Rock Blast is ore consistent).

Kind of a good question. Both SE and RB perform well, with their own advantages and disadvantages. For instance, if you're multilogging, it's a LOT easier to use single-bar charge moves.

If you have either SE or RB on a Golem, it's really not worth using a charge TM to get the other move unless you're drowning in TMs or something.