Nonsense.
Here's the most accomplished bodybuilder of all time before steroids got in the sport. 5'9" 185-195 lbs:
That's the absolute natural genetic limit with perfect genetics. You see guys ALL the time more muscular than that, even taller guys. It's absurd.
Google old time strongmen (not body builders - that was never popular in the 1800's, when actually being strong was important rather than appearance). Your Google images page will have many examples of men more muscular than that.
Again, if you have a visual inspection system which can determine that someone is using steroids just by looking at them, don't waste your time on Sherdog. The IOC anti-doping committee will pay you millions for it, because they would love to replace blood tests with a visual system.
Do you really think that people like Dick Pound haven't heard of all the visual signs that make up Bro-Science? Ask yourself why they haven't been implemented. Hint: its because visual systems are even less reliable than blood tests. Now if you have a system which is reliable, you're a rich man. But I'll believe it when I see it being used.
This visual inspection stuff is the same kind of conspiracy theory as the fake moon landing crap - people think that the sporting bodies are either ignorant of or suppressing all the bro-science which can tell by looking if someone is using, no doubt because the Illuminati or the CIA or the KGB or something like that loves blood tests and so keeps these definitive visual tests so secret that only the enlightened people on Internet forums have heard of them.
Visual inspection isn't used, because it doesn't work except in extreme cases. Once again, if your system is different, then you are a rich man. If not you're doing the testing equivalent of astrology.
There are a lot of reasons to think most UFC fighters (including GSP) are using. How they look is not part of it. Anyone involved in any aspect of testing knows that. The sporting officials, who would love to be able to disqualify someone for their appearance (talk to them, you'll learn how big a headache the whole blood testing setup is and how much they hate having to use it to determine who is using PED's), know that they can't because appearances don't prove what bro-science thinks it proves.