Being on testosterone replacement therapy (TRT), we don't have to worry about the quality of our test since the pharmacy is not likely to make a mistake. That being said, yes oily skin seems like a pretty good sign your test is OK. My skin is noticeably more oily now that I am on testosterone replacement therapy (TRT) and my test levels range from the middle to the upper end of the normal range. In fact, I pretty much have to shower every evening to get rid of the excess oil or my skin breaks out.
Lucius