Del Mar Sliding door rollers Pat 3,670,257

Hello, I have several patio doors requiring roller replacement. The doors date from about 1977 and all use Del Mar single rollers. The rollers do not have model or part number markings on them, but are identified as "Product of Del Mar Eng. Co, Long Beach, Cal. Pat 3,670,257." I have looked at the Del Mar on-line catalog but can't find an exact match. Can you recommend one that I might try? The roller housing is rectangular, approx. 1.4" high and 2.05" long. The front-to-back dimension is about .6" and the wheel appears to be 1 1/8". I can send a photo if that would help. Thanks.

Here's a pic:

Paul -
Thanks for your quick reply. That 81-243 looks like a good fit. I'll give it a try.
Bob