I believe that 1-40 thru 1-63 series and the 250's and 300 Macs are all the same 80cc saw with small differences. Most of the parts will interchange. This might help you on your hunt. I have been making gaskets from raw material. They might still be available though.
Also, a 15 has many parts that interchange. there are some differences though. I know I can only list so many, but the obvious ones, are the carb and air cleaner, and the cylinder is more vertical than the horizontal position found on the 1- series and others.