I think that the engine mounts are the same, but the LH has a different location. (RH has 2 holes in it already). The real issue though is with the transmission. With the 1HZ the transmission sits further back than the 1PZ. So you either need to change the transmission location or both engine mounts.
You are correct about moving one engine mount but the transmission mount sits in a different location because the 1HZ uses a H55 while the 1PZ comes with the R151 and that mount sits further back I believe.