Seems to me like you are going to experience one year of depreciation really fast just to have a truck a few months earlier. Five years from now, your 2021 will definitely be worth a lot less than a 2022 even though you only had it a few extra months. I would hold off and make sure what I got was labeled a 2022.
I can see if your paying top dollar for it and maybe then some. Yeah you would want that truck early in the MY. If you can get a Gen 3 for MSRP or less then getting it even into the fall is certainly fine. Depends on what you save and really how badly you want or need to need to be in it.