644 / 650 baler follower roll compatibility

I managed to destroy the follower roll in my 644ss two nights ago. Took out the scraper assembly along with it. I already needed sledge gears so I'm looking to do it all at once and with used parts. I just don't use this baler enough to want to dump a lot of money into it. So I'm looking at used parts and the salvage yard ten minutes away happens to have a 650. Every part number in the sledge appears to cross over except the follower roll. Any ideas what the difference is and whether it would still be a drop in replacement even if not the same as my 644? My baler has the cleated roll with expeller and the 650 is smooth but I'm not too worried about that. I've made about 50 silage bales in the 5000 total I've put through the baler.

644 / 650 baler follower roll compatibility