All we can do is ask. Leave the decision up to the staff. I'd say that a .mil radio forum should be open to any radio that has a military format identifier on it such as AN/PRC...anything. New or ancient, it's all good.
Looking through the subforum list, it's certainly not any more obscure than some of our subforum topics we already have.
The South and Central America subforum has TWO....I say again....TWO threads in it! If that earns its keep then a .mil radio subforum is certainly likely to be at least as worthy.