No, I know Weidman doesn't walk around at 185. Do you think Hendricks walks around at 185 just because he's a WW? He's arguably the biggest weight cutter in the WW division, along with Thiago Alves. He walks around at 220 and he cuts from over 200. Weidman would have a significant reach advantage to help him in the striking department, but he would not have a size and strength advantage to help him in the wrestling department.
Also please don't even try and pretend that Weidman is close to Anderson as a pure striker. He won due to...
A.) Takedowns and the threat of takedowns which helped him dramatically standing. Chael Sonnen outstruck Anderson on the feet too at UFC 117, doesn't mean he's close to his level as a pure striker. It was all the takedowns and the threat of takedowns that helped him accomplish that.
B.) Fluke circumstances. Breaking a leg on a leg kick thats checked is a fluke, no matter how many times Weidman tries to tell the public it wasn't. Think of all the leg kicks in history, and then the number of broken legs off checked leg kicks. And in the first fight, Anderson was goofing off and got caught more than truly outstruck, even ignoring the wrestling aspect that I've mentioned earlier.
Hendricks doesn't have to worry about a takedown because of his wrestling ability and the fact that he's just as strong as Weidman despite being a WW. Size/strength would be a bigger issue for many other welterweights, but not Hendricks who is cutting weight to the point of where it's diminishing his performance in his last fight by killing his cardio due to a brutal weight cut. Kind of like how Barao might be just as well off going up to FW, too, considering his size. Difference is I think Hendricks is just lazy with his diet and if he starts taking it seriously, he should be able to get in better shape and stick at WW for a few more years, at least.
Like I said, Weidman likely wins due to superior striking. But the idea Weidman would rag doll him or badly outwrestle an NCAA D1 national champion wrestler who has very similar size and strength to him is silly. And since Weidman isn't a special striker (he's very good, but not talking an Anderson type or a Machida type when you throw out threat of takedowns) when you take away the threat of takedown, it's a much more competitive fight than people here are suggesting.