When they were transitioning to the Mark III they D&T the last few Mark IIs in production. So they are scarce. MK512 and KMK512 had more D&T about 2000 of each all other models very scarce. I am still needing 3 or 4 models to have them all.I thought they produced those for about 20 years? Or do you mean the factor drill & tap was only done to 100?
I had a SS one back in the last 80s and then got a blued one back 15 years or so. I think it's a 50th anniversary or something but have to go check.