There's more to the story. I already had a Makita die grinder exactly like the one that I found. I didn't want to take it apart 'cause it can be a pain to get back together & 'cause I expected that it would just have the same grease in the grooves. Which wouldn't help me know what kind of grease it was.
But your responses got me to wondering whether there was something other than grease there. So, I took the first one apart and found ... nothing! There was not even grease - the grooves were very nice & clean.
I've had this grinder apart before & it's theoretically possible that I had removed whatever was in there, but I doubt it. And the parts diagram doesn't show anything.
So, the question's not answered, but I don't care - I'm going to put them back together and use them.
Thanks for the replies, Bob