Yes, the MAPP has the typical Tanfo firing pin block. It looks like a CZ, but works the opposite (drops instead of pushing up).
As for sights, contact RIA. I'm sure they can tell you what fits, or provide dimensions. I would think that the major sight suppliers would know as well. Mine came with a fixed rear sight. Right after I bought mine, I saw that they offered a model with an adjustable rear. They sent me an adjustable rear at no charge.