Your stock will need to be in one piece, with missing wood replaced. Otherwise, the replicator will replicate the broken, missing areas along with the rest of the stock.
I suggest talking to the person you contact to do the replication and follow their recommendations.
I would also suggest having somene who is a custom builder and restorer do the work.
Either of these two might be a good choice.
Dave Rase (360) 479-1888.
5509 NW Gross Rd.
Bremerton, Wa. 98312
Fred J Miller, (570) 922-1861
4025 Red Ridge Rd
Mifflinburg, PA 17844-8244
I seriously doubt that any replicator will be able to replicate the inlets, so your new stock will still need a LOT of work in the form of inletting, final shaping and sanding.
Depending on what this gun is, I highly suggest that you contact a restorer to see what the ramifications of restocking might be. It could be that a restoration of the old stock might be the best idea.