Casement window, house built in 1957, replacement operator

Hello. My wife and I recently bought a house built in 1957, which appears to have all original windows and window mechanisms. Some have cracked castings, and we are interested in replacing them. They look similar to the Getty models on your website, but the overall arm length is 13.5" vs the 9" listed. That said, ours appear to actually be 9" arms with an extension that has been riveted to the end. Is this at all familiar to you and would you have anything that could work in its place? For reference, the image attached of the front of the house shows the windows in question. The upper half of the large rectangular windows hinge outwards from the top using these mechanisms. Thank you.