Sliding glass door rollers? approx 50-60 years old best gues, maybe newer?

I've actually never seen this roller before. Could there be more to this, or is this piece all there is? If there is a more extensive housing, may I see it?

I can tell you right now at least that we don't have anything in our inventory that is similar to this, in part or in whole. Judging by the age there is a good chance this isn't made anymore. If the housing is still in good condition, you could theoretically just replace the wheel. See our 81-166 and 81-272 axle kits for what I use. This is a good solution in a pinch and hopefully will make sure you don't have to think about these doors for another couple decades.