I don't know that the seal material is the same or even very quality-oriented given BMWs penchant for suppliers. I think the answer is complicated, and price is definitely an issue for BMW as well as the DIY or indy that sources the parts. It's not like you have a choice between viton or polybutylene or other materials and/or seal configuration...it's more than just ID/OD and width, spring loaded, etc. The flange seal surface is critical for longevity as well and you really can't control that. Stack up probably leads to as many seal failures but not as many as that little plugged vent! LOL.Seal material same, different sizes/part numbers.
Oil is very specific, from BMW $$$$ many argue, however the argument is price biased.