Okay as a guy that lives in a country that doesn't have a Napa that will sell me a jug of GL1 gear oil for for my r10 overdrive I may have found another option.
That option is a Shell gear oil called Dentax. It is not an EP oil but more importantly it clearly states API rating GL1. Not recommended for hypoid gears but recommended for spiral bevel, heavy duty manual gear boxes. Comes in a 80/90 which I believe the part number is 59003 but I also saw another 465 number but that might be outdated.
My shell dealer says he has in 5 gal pail but he will decant it for me, maybe 2 gallons.