Top track, missing bottom fastener to shorten length of door.

That patent number is often associated with our 23-093, but note that ours has an adjustment screw with a spring. Neither are sold separately, unfortunately, we can only supply you with the complete roller assembly. 

Also, since yold adjustment screw is missing entirely so I don't know for sure if yours needs a spring or not. Look the 23-093 and see what you think. It's important to note that patent numbers aren't the most reliable thing in the world. You don't want to trust them too much.