the flat area up above rocker should have threaded inserts for factory boards to bolt to, many of the aftermarket ones use the same ones to make them no drill
That would be extremely helpful if they were there, but the only thing like that I can see on my vehicle would be the bolt at the bottom of the front fender.
From what I can tell, running boards weren't an option for the '93 Blazer - so the mounting points wouldn't be there.
It looks like in the diagram provided above, the main support will come from brackets that seem to be welded to the inside of the rocker panel.
I've seen a couple brackets for sale on ebay, but I would need 8 of them. I don't think that's something that could easily be removed from a parts vehicle, so I may look at fabricating something.
I assumed it would be much simpler overall...