I think there are many euro guns inmaple. Quite a few in Steinschloss are maple. Consider how scarce wood was in Europe, and then when the wood started coming in from the colonies, what a fad that would have been.
Chris, you are fine using maple, in my opinion.
I am curious to see where you go from here, if you splice, or work it as is.
Just a note, the Euros salvaged many a stock by splicing and patching. Have no fear. I can provide you with photos of patches done in the stock as the gun was being built, not as later repairs.
Acer