My general experience in places like this (where concerts aren't the norm), is that the staff is completely clueless about taping. This CAN be used to your advantage as they likely aren't even looking for you. I've strolled right into places like this for bands that either don't allow recording or are borderline with my full rig...no issues. I'm going to assume that the staff saw me and just thought I was with the band. Occasionally I've even had someone come up to me and ask if I was with the band and said, yes and they left me alone after that (although in that case I knew the band members well).
Even if you do get shut down at the door a polite, "can you please ask the band/manager if it's okay, they normally are fine with recording" goes a long way.
I don't recall, but maybe someone here has a connection with the band and they can relay your request to them in advance.