I'm going through this with our car right now, coincidently enough. Your top bolt with the 'R' in the head marking is your coil bracket to intake bolt. The other two bolts with the serrated, external tooth washers are as Charles states - two of the four bolts that mount the compressor to the bracket from underneath. He's right about the dog leg bracket bolts that screw into the compressor from the left side too (front of your car looking at it). Those would be the same head marking (as your bottom two in your photo) but with a flange head, external tooth washer, as the others, only longer. Found them to be the same thread size and length as the two starter bolts, just different washers and head markings, but consistent with that flange head configuration.
Hope this helps.