Only if you shower...
Why even bother posting, aside from wanting to bust out a weak joke?
Anyways, C.G.R.
The guys I know who went CSOR and passed the Operator course retained their rank. I can't say about the other units, but I would assume it would be the same. Maybe not for CJIRU as that is an actual OT. Contact the unit you are interested in, and you can get an answer from their recruiting cell.
If you are going in as a supporter, you would retain your rank as well.
Also, passing selection just means you can go on to the SFC course for CSOR or SOAC for JTF2, etc