your style with the center loop is the old style. the new style is technically better as it allows the mainsheet to slide more freely. unless you're having issues with it, I'd just leave the current setup as is and just go sailing.
the tiller and sail definitely look just like the Catalina 12.5, but without the curved boom.
it seems someone picked up this find for $75 or less, maybe it all somehow works as a unit?
or maybe (more likely?) the seller just threw a bunch of parts together hoping to get rid of them as a...