[Jake Blake]

Thanks Mike. 

Sheesh!  I didn't even think about sticking.

The seller is acting like he wants to do this for me, but a little unsure of himself, asking for "tips" for removal. . . . .so I'm trying to compose directions  for him.
While I was waiting, I went into the back of the 89 B here. . . . but I can't figure out which of 3 sizes of nut drivers fits those nuts properly.  Now bear in mind, I've  already removed this speaker once, almost 30 years ago to change the grill cloth, but I guess I must have just used a pair of pliers. 
The 1/4" and 5/16"  nut drivers I have now, appear too small, and the 3/8" is too big.  Maybe I ran into this problem then, because I discovered, mine are only on hand -tight anyway.

What gives? Surely, they are not metric-sized !