Do you have more pictures? I am still a little skeptical since your model does not have the damage on the neck extension seen on the Ex-Astris-Scientia photo I posted. Also the bussard collectors seem a little more conical (but the neck extension damage is where I have my strongest doubts).
The damage to the neck extension would have been on the Yamaguchi model, not the Enterprise-C (your B&W pic shows the Yamaguchi.)