We must have bought the same stuff, my corners also will need ground for the trim to fit in properly. I think the ones I have are pace, at least they look like the cast corners on my trailer. Typical, most enclosed trailers are just slapped together and look pretty on the outside, except for the premium brands. I pieced together the curved corner sheet metal from a few different stacks at the surplus place, so I knew I'd have to finagle there. You know if all the rv and trailer manufacturers had the same standards as the builders on this site, they'd be way farther ahead. Of course nobody could afford them...