I didn't know they made high temp primer. I would be pissed. You need to have him reblast the inside just incase the paint/primer starts to flake off. You need bare metal so you can season the metal with oil kinda like you would with a dutch oven.
They don't make high temp primer. If you talk to any professional paint shop they will tell you to make sure the metal is clean and use only high temp paint, no primer. I have painted many a smoker with just high temp paint and had no problems.
I still don't see that its a primer. Good high heat paint is expensive. I don't remember what i have paid for mine but I know it was over $100 a gallon. The fire box is the only place the paint will come off. I just give it a spray of oil when it cools down.
Looking good. But don't care for the hinges they probably wont last very long, next time make your hinges out of pipe and rebar they will last forever.
Looks like you are having fun!