rolex 18038 question

[goldintl]

Hey all, I own a few pieces but never experienced this. I got a lead on a local 18038 it was in good condition a little worst than what pictures described nothing seemed out of the ordinary a small ding on the case.

I inspect the watch and serial number has obviously been polished off compared with the reference number on opposite side that is visible. I bring this point up dealer puts on a loup and says he can make it out no problem.

I tell him I want to get it serviced at rolex and he tells me not too he'll do it for a fraction.

Either he was trying to pass me off a tampered with watch or the serial just fades away ? Anyways I felt un easy so I gave my apologies said i won't be taking it and left.