JWALKER may jump in here but my $.02 worth is that the mirror probably wasn't made by Damon. My mirrors came from RAMCO. I'd call them and describe your mirror and I'll bet they can tell you who made it, if they didn't
On windshield wipers, I've bought them from Wal-Mart, O'Reilly Auto Parts and Camping World. If you have the correct length (probably around 26") many places will have them.
MH makers hardly make any parts themselves. Most of the stuff comes from different suppliers who may or may not still be in business within a couple of years. I finally tracked down parts that I needed for a compartment door hinge and they were indeed made by someone other the Georgie Boy. The problem was getting through Coachman and then Forest River to someone who knew about those parts and where to get them. That is the problem with so much buying and selling of companies is done.
2000 Georgie Boy Landau 36' DP
2018 Equinox toad