As nice as you think that stock is/was, I think you would have been further ahead by getting a nice fitting stock, and adding the epoxy fill in those type of areas to add color.
It looks like the original stock never fit proper to begin with. Much more, better photos on their facebook page about this stock for sure.
Wonder if it might be worth your time to fill the finished stock up to the new bedded height of the action. Another words add materials to your stock to build up the stock to look, sit proper to the action, and then finish it properly? I imagine that would be lots of work, and quicker better to get a new good fitting stock and add the "river" look to it.