An RV service center should have parts in stock. You can probably get them directly from Hehr Window too. I have replaced nearly every part at some point, with my previous campers. Some parts replacement require complete window removal just because it is much easier than trying to hold parts together in a vertical situation during assembly.
2000 Winnebago Ultimate Freedom USQ40JD,
ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy