By boot camp I assume you mean Marines? Army is basic training.
Anyway, Army Combatives is largely based on Jiu-Jitsu, and also incorporates Judo throws. Wrestling is well known as being an advantage when you learn Jiu-Jitsu because you understand base (control opponent).
Honestly, any sport will help, not just wrestling. Choose what you like and go with it. Passing a PT test is based on push ups,, sit ups, and running. Most important is running. So any sport that is active will help you.