u/Dull_Papaya_5510

I’ve got an ‘83 xv920 project bike, and have a question on the final drive gear oil. Manual calls for SAE80 gl-4 hypoid gear oil. Which is a combination I can’t seem to find anywhere for some reason. Is there any yellow metal in the final drive that would prohibit the use of a gl-5 oil? Thanks in advance for any info.