I have a 2015 2500 HD and I have the Ranch Hand grill guard, I know the difference that you talk about between the older model 2014 Ranch Hand grill guard and the 2015 and it never really bothered me.
big question I suppose would be are the vertical steel posts on the 2014 and 2015 RH grill guards in the same place, same dimensions. These mount into where the factory tow hooks mount. Also the curved geometry of the steel tubes maybe different between the 2014 and the 2015 grill guards. If that 4 inch exposed grill section is a problem, you could always have a local shop modify it for you.
Looking back I wish that I went with the Ranch Hand Bumper and grill guard instead of just the grill guard, I still might do that one day. I have a Ranch Hand rear bumper also on my truck and later this year I want to replace the factory running boards with Ranch Hand step rails.