The 421 has had a bass roll-off switch ever since the '60s. The really old early ones had a bass cut that was more like a sliding rotating thing without clicks (detents) that would roll bass out. Later it became a 5 position switch and was always there on the 421. It comes in handy sometimes when proximity effect is a problem and you don't have enough control at the board for precise hi-pass filtering.
It really is a mic that belongs in anyone's mic collection. It was all over the Dead's stage for years. It's the classic kick drum mic for the Dead. Tom mic too. They even were singing into them thru the mid/late '70s and early '80s. It's quite the classic Grateful Dead microphone.