Pocket door hardware
We unfortunately don't sell a pocket door roller that matches what you show here. Our selection of pocket door parts is admittedly very small; these doors just aren't as popular as they used to be. Based on the age of yours I would also suspect that it hasn't been made in a long time.
As for the wheel itself, we don't have many concave options at 7/8". The only options we have for that are screen door wheels like our 84-057 and 84-017, but both of these have a 1" diameter. They'd likely be too big for your application.
The only other option I can offer you would be an all new kit like our 23-250. However even a new kit has no guarantee of working.
I am sorry that we can't offer you anything closer.