I've never had that question come up so idk. I'm not sure it's possible because payment is online and the transaction processes in a completely different way than a store purchase....thus, no paper receipt given upon pickup.
If you go to the guest's transaction in MyGO, there is a receipt ID and VCD. Type the Receipt ID on the register, press enter. It will ask for VCD, press enter after entering it. Then you should see an option to print a gift receipt. Mind you, I haven't touched a register in about 6 months, but that is how it was when I was there.