944 and 950 brake shoe compatibility

Hello All
I decided that while I am rebuilding the engine in my 944 that I would also free the brake cylinders up and get them working. The front were no problem but when I removed the rear drums I found the previous owner had removed the brake shoes. I cannot find any of the brake shoes to suit the 944 except from Cat and they are priced out of contention. I did however find some brake shoes that fit a 950. According to the parts manual I have for the 950 they share the same drums, wheel cylinders and spring as the 944 but they are different parts numbers. I have parts books for 944 from 43A1587 - 43A3011 and 43A3012-up that was published in April 1971. Production ended in 1968 so I assume I have all the latest parts books for the 43A machines. Does anyone have a 87J parts book to compare?
950 brake shoes = 4K-3504
944 brake shoes = 1K-8822
There are three different backing plates listed. The bottom pivot pins are also different parts numbers so I may have to make up new pins. I am hoping the different parts numbers are something simple like different lining material.

Regards

Phil