Hi Glen, yes that has happened before. Jeff, from PNWZR-1.com, aka Jeffvette. There is a thread here covering that. Just do a search under Jeffvette. He ran into that issue on a customer's car. However, those headers that gave Jeff the install grief were made before the ones being sold in our NetRegistry store now.
The headers in the ZR-1 store are a new batch from new jigs. I believe it was the old jigs that had become "worn out" (?) that caused the fittment issues. I am under the impression that even when the pipes were dead on, that there was never much clearance for the #1 primary pipe going past the steering shaft, maybe 1/8" at best. That is all from memory so check the thread out to be sure, cause I suffer from being senile sometimes. I would call Jim at Stainless anyway as that would be the definitive answer.

Tom