I agree with David's answer. The crown will only live 35 to 50 years, but the rhizomes will make sure something stays in that general area. So they could be a mutated/feral version of whatever was planted there years ago. I also agree that they probably didn't produce due to lack of nutrients, trauma, lack of water, etc. If you are nice to them, something will pop up next year.
Before you do brew with them, make a little hop tea to see what the flavor would be like. I've found some feral hops before that I wouldn't use in any style of beer.