HI: FYI
I took up a 8MM X .75MM / STRAIGHT Zerk and it worked fine.Put a couple of light grease pumps in and we be done.
It was done for convenience more than anything as the other grease gun fittings would have done the job with just the threaded plug removed.
Back in the day I had to machine a new cross shaft(?)(see attached diag) and the reason being shaft corrosion was making shifting more onerous than it already was.I put in a zerk fitting in the culprit area so that friction point would always be well treated.