Yes but there are people who build completely new and better servos for the RS1b and IRS. That servo,wasn't the highlight of the speaker. My good friend and colleague had his redone years ago and you didn't need a one speaker trial replete with 100 charts and diagrams to hear the difference. nor any shills.
I'd be more worried about the shape of the ribbons.
So it will add a little more cost but then again this is a classic speaker in the classic sense. I didn't remember that only 39 were made but I heard 6 pairs (and helped set up two pairs) in the NY area including HP's. The IRS still sets standards for a full range speaker (very few speakers if any can move the air that the IRS does and bring music to life) and resolution. The IRS because of its revealing nature does more than any speaker require the best in associated electronics and front-end components. You will not get away with entry level electronics nor a crappy front-end. The IRS also were back then partial to tubes. Whether they still do with current ss electronics is an open question.
They also need the right room; I heard one pair set in a room with flexing walls and no matter the owner did, there was no midbass. I heard them at HPs and they worked in the small room with it's thick wall and near field listening and they also worked in the big main room.
One might also look for a pair of Betas; Paul's new pair sounded mighty impressive.