I think on a 16" barrel you need all the help accuracy-wise you can get. It's not that much more, and surely doesn't hurt anything.
It's really not hard to install that later on. I'd actually recommend spending a little more and getting a Midwest Industries 2 piece free float handguard. I ALMOST got the YHM ones, and decided to spend a little more on these.
Since they're 2 piece, they install just like regular handguards, and don't require you to take the entire upper apart. You just pop yours off, cut off the delta ring, and put these on. (You can take the gas block off to get the delta ring off, but that's your call).
This is a much better setup in my opinion. The YHM leaves a small gap between the upper and the tube... this one does not. It looks MUCH better if you pay attention to that stuff.
Given your choices, though, I'd say the lightweight if you insist on getting in installed from them.