I hope so, as I have several of his rookie and insert cards. In reality, there were better pitchers, statistically. And are we talking about starting pitchers and relief pitchers? Within relief pitchers, there are middle relievers, long relievers, set up, and closers.
If we are strictly talking about starters, without looking into the numbers, I would venture to say Walter "The Big Train" Johnson, Grover "Old Pete" Cleveland Alexander, or Christy "The Gentleman's Hurler" Mathewson were better starters than Randy "The Big Unit" Johnson.