circular saw

I have a very nice, likely a 1964 or 65 (based on the serial number and some information I have available to me) HOMELITE XL-100 gas powered circular saw. This model fits up to a 8 1/2" blade with 5/8" arbor. It has been meticulously cleaned both inside and out (short of total disassembly)...

My friend and I each own Homelite XL-100 Circular saws. The gear cases are full, but would like to be sure they have the proper oil in them at correct level. These saws must have been built like tanks. Both still working and over 50 years old. Thank you