I guess I'm in the minority on this one. I say as long as the price is in the ballpark, why not?
My reasons are as follows:
6 additional ounces is not that big a deal, unless they're out near the flash hider.
Right now, you may not want to hang all kinds of crap off the handguards, but later on, you might want to. If you already have the rails, you can. If you don't, you'll have to make a way.
Why limit your options? I love a .357 revolver because you can shoot everything from creampuff target loads to "stop an Oakland Raiders tackle in his tracks" hunting loads. My AR has a Wylde chamber with 1/8 twist because it's supposed to be able to chamber just about any cartridge, and shoot just about any bullet weight. If expense is not an option, why limit the accessories the rifle can wear by not having a rail?
You can always change it to a standard handguard later on fairly cheaply - you can't add a rail to a standard rifle nearly as easily or cheaply...