Replacement of pivot cams for 1983 Marvin windows.

We are replacing window jambs on Marvin windows that were installed in 1982 that are made with vinyl and a spring installed inside. We now have all of the vinyl window jambs for the house, but upon looking at the working mechanism while removing one of the windows one of the pivot cams broke. I'm afraid this will happen again since we are replacing all of the window jambs. I'm looking to buy pivot cams to have on hand if this happens. They are marked with either R or L with four spikes on the backside that looks like they were hammered in. Do you have these, or some other cam that would work? Attached you will find two pictures of the front and backside.

Thank you.
Keith