Honesty time:
I performed an experiment on myself when I did the ergo clear mod on my Pok3r. After lubing about 1/3 of the switches, I stuck them into the plate and then stuck some unlubed switches into the plate also. I played around with them for a bit, and thought that I could tell that the lubed ones felt a little less scratchy.
Then I thought that maybe I was having some confirmation bias? So I stopped lubing the switches and randomly mixed the lubed switches with the unlubed. Guess what? I failed to be able to discern lubed from unlubed. I wasn't sad, though, since that saved me the trouble of lubing the rest of my switches

At that point, I went through and found enough lubed switches to use in the stabilized keys and then let the rest fall where they may. I just wanted to make sure that I wouldn't have any trouble with the keys getting stuck in the down position since I was using really light springs (equivalent to MX Browns).
Maybe some of you out there can tell instantly, but when I did a blind test, I couldn't.