Out of curiosity, I put a G250 together that way. Breathes better than I would have expected.Yes between the balance chamber and the adjustment knob. It worked but breathed very hard (compared to how it should).
@buddhasummer If it does turn out you need replacement, I have a few versions of G250 on hand and could probably get one to you (or even just a case) at a much better price than giving away a new G250V. Hopefully the responsibility will fall on the person or entity who botched the job or got mixed up though. Sounds like you tried to be helpful and ended up with the short end of the stick.
I made an online purchase of a "serviced" S600 for my wife last year from a SP authorized dealer, upon arrival it was clear the regulator had not been opened up for some time. They accepted responsibility with partial refund plus a couple service kits, but yet another example of Why DIY?.