ORIGINAL: earlwb
I don't know if there is enough material left in the piston to cut a couple of grooves for a small wrist pin retainer ring or not. But one could do that to keep the wrist pin from moving. It isn't easy to do it though. But when you rotate the cylinder, you'll need to ensure the ports match up with the piston OK and that the piston skirt doesn't hit the backplate or crankshaft either. Oh yeah, some companies actually drilled a small hole in the piston and wrist pin and pressed in a small roll pin too. One could also cut a groove on one side of the roll pin just on the inside edge of the piston and put on a wire retaining ring there too, I remember seeing that on some old vintage engines before. I have even thought about just using some J&B weld epoxy to lock in the wrist pin too. The cylinder and piston isn't all that expensive to try that on either.
The ports should be okay in a rear exhaust setup if the wristpin issue were out of the way however the engine would have about 2 degrees of sub piston induction as a rear exhaust. The backplate is not machined for the transfer port that would normally be there and the boost port would be shrouded by the crank counterweight somewhat. If one made a new backplate with a recess for the piston it might improve performance some but I wouldnt know unless I tried it.