First, Thanks to all, especially Silent Bob for posting all this valuable info.
I stumbled upon a bit of info that might be helpful to someone out there:
My tale: Ram 1500 ordered Feb 19, 2021. Status D for a month with no changes. FCA incentives hotline
( 1-800-227-0757) was helpful, telling me exactly which March rebates could be preserved by the dealer using "sold order protention" as my vehicle would clearly not be delivered anytime soon.
My dealer (a 'friend') was not interested in troubling themselves with going through the "sold order protection" effort to save me money.
Any GOOD dealer should be willing to implement "Sold Order Protection" for their customers according to the FCA Incentives Hotline rep. Rep even said the dealer could call them if they were unsure how to do it! If you have a truck on order, I'll suggest you attempt to lock in the March incentives should your truck be delivered after March 31. This presumes the incentives won't be as big after March, a fair assumption.
Moving on...I ended up driving 40 mies to a dealer who had on the lot a nearly identical truck to what I ordered. Started with a below Invoice dealer price, got all of the rebates and incentives I could get , and then 0%. Cancelled my original order which I would have been glad to wait for if only that first dealer would have shown some interest to helping me preserve the March incentives.
So, as of yesterday, I own the new 1500, ended up with a fantastic deal due to all the advice presented here. THANK YOU!