Yanmar makes a YM155 and an F155. I suppose you are speaking of a YM, and the YM1300 is the gray equivalent to the YM155. Dead ringer almost, and the loader is a bolt-on. The Koyker 80 is the way to go.
If this is a 4wd, keep in mind that the front axles on these aren't real tough as they really weren't designed for a loader. If it is a 2wd, it will be dissapointing with a loader due to weight transfer off the back wheels.