I think it depends on the condition of the broken stock. If a clean break and the wood isn't rotten or oil soacked beyond relief a very good smith like Keith Kearcher can repair it almost invisibly and the repair would be stronger than the original stock in some cases.
As a collector first and a shooter second, originality, even if repaired outweighs replacement in my book. However, I accept that some will feel strongly the opposite.

Great-Great Grandson of D.M. Lefever
www.lefevercollectors.com