Counter shaft o ring(s) different size than the parts' list says?

[steliost]

hello people, I went on to repair my leaky front sprocket on a EC 300 2005. I bought a seal and a couple of o rings (ID 25, 2 mm thick by the parts list). when I took out the old O ring I noticed that it was smaller in ID and thickness, i.e. 23mm and 1,5 respectively. also it was the only o ring in there, I thought there were supposed to be two? anyway I bought two new rings but managed to fit only one with the new circlip barely getting in the groove nice and snug. there seems to be no room for the second ring unless I shorten the sprocket by 1-1,5mm on a lathe to get the second one in and clear the clip groove or deepen the inner step on the sleeve by 1-1,5mm to accommodate both o rings. Is any of those options viable? previous circlip looked a bit worn and possibly didn't push the sprocket deep enough to press the ring and it had a bit of play. Did I do something wrong here? I contacted the mechanic that rebuilt my engine a few months ago and he told me that, indeed, there is only one ring in there... The ones that the parts list commands (25X2) don't fit in the step of the metal sleeve but the smaller ones (23X1,5) go like a charm and seal well on the shaft but as I said before, only one of them went in... should I put both in and really struggle to put the clip?
Is there a chance some models use different size o-rings?
So did I f*** up or am I in the clear?

many thanks in advance.