factory style mirrors

[19GMC63]

Got tired of the crappy peep mirrors and remembered the truck came with a brand new pair of repro round style mirrors w/ rubber and screws. But the PO of the PO must of filled the original holes.

Anyone got a close up pic of where on the door these are mounted? Guide measurements would be even better. And as far as the screws go, I'm guessing there was some sort of backing plate with weld nuts or something?

thanks