Bauer is a pretty smart dude. I wouldn't immediately dismiss anything he says about pitching.
Verlander went to the Astros August 30 last year. He is probably the best example to look at.
Values from 2017-2018, before and after the trade...
FA: 2536 RPM -> 2603 RPM
SL: 2510 RPM -> 2633 RPM
He added spin rate with the Astros.
Did they immediately teach something to a 35 year old pitcher that he was immediately able to implement?
Or did they have him use something sticky on his fingers?
If they had him use something sticky, does anyone really think they are the only team to know about using sticky stuff?