The GWS flight packs don't come with a crystal. You can NOT use the Futaba RX crystal in the GWS RX, you need to get a GWS crystal.

There are some RX brands that have interchangeable crystals, but they aren't all interchangeable.

Also, the Futaba RX is almost certainly duel conversion, while the GWS RX is single conversion. That means the Futaba crystal can't possibly work in the GWS RX.

So, go get a GWS crystal on your TX's channel, and go fly