It wouldn't surprise me that Alvin figures his personal judgment supersedes the posted wording on the BLM website. I have also seen him reject a PFD for slightly frayed straps. I have an legit firepan, so I don't have to test the notion that he has to follow his own regulations. But I can also understand if someone had to balk at dropping $200 for a 'certified' pan, and if you gotta take a chance I'd print that BLM page to take with you.
FWIW, I used a galvanized pan for a couple of years in the 90's, and have seen plenty of galvanized pans checked in at the ramp since. Just bring a dedicated ammo can for the charcoal.