Your right. Their process takes a customer selected, or provided blank and uses nothing but the selected blank to build the stock. This enables them to keep the "show" sides visible and avoid the "plywood" look of most laminated stocks.

I've used the open sights with the Merlin configuration, and it is a slight compromise using them. The stock is mainly designed for scope use, but with a bit of experimenting with different sight heights, I found a set that fits my chubby face. It's much more comfortable to shoot with open sights than the original factory stock was.