Hey all, just discovered this: If you have an old BCA float bag with the v1 canister/head, you might not be able to get them refilled. The v1 head, where the serial number is etched is solid (there is not little brass colored disc...which is the blow off-disc/valve in the case of over pressurization during refill process...as was told to me yesterday by the refill gal). However by getting a hold of the warranty folks at BCA (see link below) they will get you squared away with one that can be refilled.
https://backcountryaccess.com/services/warranty/