Hi Mark,
Going back to my 1963 Military oils book and talking from experience, the army only had one Straight grade (non-EP) gear oil, this was OC600, which was SAE140. This was to be used on any worm drive axle or any axle or gearbox containing bronze type metals. Where a thinner oil was needed in gearboxes, but not an EP, the army specified a SAE50 engine oil OMD330, such as in Bedfords, etc. Other than that it was OEP220 normally.
In your quote, I think you mean OEP220.
Richard