engine break in with new headers?

you have a 50/50 shot of them being fine. For the money, I'd pop on a cheap set of logs to break it in backpressure wont hurt anything..With any coating like that, if you start it with them, run until warm, then shut off ant let cool of..do that cycle a few times before you go and whip up on it..the finish will stay nicer longer, and will not rust as quickly.