I think I've solved this mystery, I ran the P/N a while back and knew my cover is for an M880, but I didn't check the frame. I ran the numbers on the parts, and they're for a CUCV. I guess the M880 cover is a bit taller?
I wasn't sure if the cover and frame were bought separately by the previous owner but if they came together then it makes sense that the bows have been mudded to fit the taller M880 cover.
Good thing I checked the M880 manual again, too. I have some clips on the top sides of the cover for rolling the sides up, but there's no strap to put into them. I now see I'm missing a part and roughly where it's meant to go.
View attachment 864720