It's hard to see from the picture if just the bill is gone, or skin with it? If just the "lips", then no problem. I don't think you will be so lucky. The odds are, that head and neck took the full load as well. I assume he swatted it (and I'm not judging....Could care less really). The duck tends to get a full load. If you post up a closer picture of the head, we could give you a better idea?
As far as swapping heads? Yes it could be done. Might cost you a bit more, and depending on the talent of the taxidermist, it could show the Frankensteining.
Either post a close up or take it in and let your taxidermist decide.
Good luck, and congratulations to the boy!