*All* OM1/n (and OM2/n) need a CLA anyway. Otherwise they get destroyed by the internal seal foam. It's the same stuff as the light seals. Test their state and you know what to expect internally. If they are not sticky ask the vendor whether the stuff inside got replaced too. The replacement of the light seals may have been a DIY-job. Changing the internal foam definitely is not. Still being adjusted to mercury cells is a hint that the replacement of the light seals has not been made by a qualified repairsman.
If it gets a CLA, it's not a big deal to adjust it to 1.5V and use silver oxide batteries.
Besides an OM2n I own a very early OM1 (I've been told that it must be one of the first hitting the marketplace in Germany). I've no problems so far but I don't use it often anymore.