Even with it being a 20lb difference, there's not that much of a difference.
Less definition for certain, relatively same mass more or less. People act like you stop taking PEDs and you instantly lose any benefit and you're gonna drop 30lbs of muscle. Maintaining muscle mass is much easier than gaining, and while you're certain to look different appearance has nothing to do with performance. Depending on the PED, they change how you're able to work, how the body absorbs nutrients, how quick you tire, the amount of O2 in the bloodstream, how quickly muscles recover from exertion, etc. Size and appearance is the least concern of an MMA fighter.
More importantly; somebody who's been taking PEDs his entire career and then stops for a year is not the same as somebody who never has. The former was able to breach plateaus he never would have been able to and make gains his body ordinarily could not. Then remember this is MMA and not a bodybuilding competition; how much extra time does a PED user get to spend training technique, when his body is able to recover from his S&C that much quicker?
As always, of course, War Vitor. Hope he knocks Weidman's head off. That said if weidman wins I couldn't be upset, the guy's nothing but class.