Thanks for posting. We've come across this roller a few times before. We have no exact replacement for it and I suspect it's no longer available anywhere. We had a customer with these same rollers use the 81-279 as a substitute, but it took some adaptation to pull it off. The 81-279 is secured at the top of the roller housing using a screw like the 33-103. Because your old roller is designed differently, what this customer had to do was cut a small piece of metal out of an angle bracket and he screwed it to the front of the roller. This gave the roller a small lip to hold it in place, just like the old roller. Alternatively, you could remove the bottom rail completely from the door so that you could drill and counter sink the head of the screw so that it would not interfere with the glass.
Finally, I've listed a few other possible substitutes on this page, but I have doubts any of them will fit your door. Let me know what you think, or if you have any other questions.
Sure, if the housing is still in good condition then that would be a great solution.
It looks like your wheel is 1-1/4" in diameter, which aligns with our 81-228. This is 1-1/4" dia x 5/16" thick. It's also fully compatible with each axle that comes in our 81-310 axle kit. Now, whether those axles will also be compatible with your old housing, I cannot say. But I do think this is a good course of action to consider.