Joinery on green cut wood sounds like a bad idea for a bow splice, especially if you want the joint to hold. Wood will shrink/ move/warp in length, width and thickness as it dries. A joint cut when wet, and then dried out won't fit very well, maybe not at all.
Different species react differently, to the stress of drying. Some woods might handle a heat gun on wet wood without cracking, most won't. I would think a light softwood like Juniper, semi dried would handle this approach better than say a dense hardwood like osage.
I personally wouldn't bother unless it was built as a survival bow in an emergency situation.
Given that Eric has had some success with the matter, I would like to hear more about the types of wood that were successful, and how green the wood actually was before cutting the joinery. Obviously the greener the wood the more movement of the wood.
There are ways to safely speed up drying, cutting down a year or two wait to a month or two. Roughing the billets to nearly finished dimensions, sealing the back and end grain, then putting them in a hotbox where you can slowly increase the temperature.
I have made some furniture out of green wood, frame and panel chests. They were made this way in days of old. The wood is rough worked to dimension, then left to season for a period of time(the longer the better at least 1 month. It is then worked to final dimensions, and mortised. Then assembled, and then pegged across through to joint to mechanically fasten the structure together. No glue used at all. It is a very different application to a bow splice or the stress that a bow undergoes.
The piece continues to season for a year or two. The previously flush joints and tightly fitted panels, are not as good cosmetically because of uneven shrinkage. They are structurally sound though. It works but is nowhere near as good as using seasoned wood, from the start.