One thing to check on is if the current MR-03 servo motor will fit within the Overland servo gearbox assembly. The early ASF boards used the old servo motor and has since switched over to the coreless servo motor which may be different in size?
You will likely need to rewire the steering as I'm sure the MR-03 wires to the pot and servo motor may not be long enough.
Overall, I'm sure it's possible, just a question of how much effort and
which ASF board.