Well, off hand, I would guess the original 70's tone control (muffler) knob was replaced with an older, small rotary knob. To the best of my knowledge, a B/O badged drum would have never had a small rotary knob. That's my guess.
Just a thought here, as I continue to seek out info on Ludwig tone control year/specs
My '71 Ludwig Standard snare has a 3/4" (small rotary knob) tone control - as far as I know, it's the original. Does anybody know what year Ludwig made the switch to the larger 1" knob? It's gotta be later than '71 - unless they were using left overs up.
That pic also looks like a metal washer, not nylon - same as my '71 Standard. All of the large knobs I see have nylon washers. I know this is slightly off thread topic, but I think that it helps to illustrate the possibility that this snare has its original tone control, not a replacement.:2Cents: