Correct. If you're using the right kind of flash hider.
A standard A2 or A1 birdcage is not long enough to bring a 14.5 barrel to legal 16 if permanently attached. A slightly longer flash nider is necessary such as a vortex, phantom, AAC blackout, etc. Many of the suppressor industry quick-mount flash hiders also work very well for this including Gemtechs, Surefires, Ops Inc., Yankee hill, etc.
I personally use Gemtech Bi-lock flash hiders because they give me that little bit of extra length, allow me to attach my suppressors, and look a lot better then any other hider on the market. (personal opinion to be sure)
Just remember that if attaching a suppressor quick detatch style flash hider, use peel washers and NEVER use crush washers if you ever plan on mounting a can. Always visually check concentricity of the bore to the flash hider (the human eye is pretty darned good at spotting offset which can be really bad with suppressors), and make sure that the weld on the pin doesn't interfere with the mounting of the suppressor.