The brass body of the roller measures 2 1/4" long x 1" high x 5/8" deep not including the screws or the roller itself. There's a marking 175 or I75 stamped on. I believe the doors were originally fabricated by Atlas Window and Door in northern New Jersey. They are no longer in business.
Casey from SWISCO responded:
January 22, 2021
Hello,
I would recommend starting with our 81-011 and carefully comparing the width and thickness of the housing, as well as the diameter of the roller, to yours. Thank you!