Replacement rollers/wheel assy

Hello,

I have 2 screen doors I need all new roller assemblies for. The doors seem to be able to be completely switched upside down and have same assembly on top and bottom. I have it flipped upside down now as a temporary solution. These are old aluminum (1970's I'm guessing, nothing in house is upgraded and it was built in 70s but I rent so not positive on that). I cannot find anything matching on google that looks the same. I have attached pics. Please advise if you have, cost, or any more pics/information is needed. I cant seem to find any identifying numbers or letters on part or door.