I had placed a hold as well, waiting for the tax credit, but with the new "referral credit" and some other circumstances, it made more sense to try and get it now. Removed the hold on 12/7. Got a VIN assigned on 12/8, and a scheduled delivery on 12/11.
Didn't do anything "special" besides remove the hold from the app, and then complete the financing terms and credit app via the app (for a lease). At first, it didn't show the $3,750 discount, but after about 30 minutes, it reflected that in the details of the final pricing / monthly payment.