Sounds like you are saying you found a deal ...
Maybe you are asking a question ...
If I understand the question, my comment is "Make sure you know who is going to fix it if it breaks" ...
I'm good at messing up my PVS-14s ...

But PVS-14s are ubiquitous so anyone that can work on a pvs-14 can work on a pvs-14. Not sure that is true for a pit bull housings ... but maybe ... but if you are not the one that will be fixing it, I would ask the person you've picked if they can fix it. If so, then you are good to go!
That said, If it was me, I would get pvs-14s and that's what I did (I have 2) because I know anyone that can work on 14s can work on them, so I'm not dependent upon someone who will work on a non-standard widget (or a pitbull).
Also are you sure the helmet and the mounts are the ones you want?