Need replacement hardware for sliding glass door

I went to Home Depot looking for a replacement for this part, but all of the parts had an extra part on the side with a hole in it, obviously to attach it to something with a screw. This part doesn't have that. The part says "Del Mar Eng Long Beach" and then what looks to be an unreadable patent number. I bought a replacement roller but I think it will be hard to remove the other since it is very rusty. I'd rather replace this entire metal piece. Thank you.