Rogue RP 1 preamp curious incident

Last year I bought a Rogue RP 1 preamp from a very reputable AD that was a store demo. I had read that the early models had a gain issue that was corrected in later models and the dealer said this one was fine, as it was. I used the unit for a year and was extremely delighted with the sound. The dealer did leave some vintage Amperex tubes in the unit that sounded rough so he gave me a set of modern tubes that worked fine. 

I recently sold the RP 1 because I am using my Exogal Comet DAC as a preamp. The Comet sounds great and I am happy to have one less box on the shelf. The sound, in my opinion, was moderately better. 

The buyer told me that the performance of the RP 1 that I had been using for a year suffered from "white noise." He further stated that he called Rogue and they identified the unit as the 13th ever made and that these early models had a white noise issue. Being an excellent company as they are, Rogue volunteered to fix this free of charge.

Has anyone ever heard of such a thing? I am developing a complex over not hearing this supposed defect. OK, I am 68 and listen to classical chamber music, but the preamp sounded great. Do I have tin ears or is this some anomaly? Also, the fact that the unit was a successful demo from a fine dealer argues against white noise. Very strange.