Canada here.
I ordered an Elevation crew cab, standard box, Duramax, in October 2022. Order wasn't even accepted until January 2023.
As of Feb 20 it didn't have a build date, so I bought an SLT off the lot. Even then, I haven't seen a single 2023 with the Duramax on a lot that had the multi-pro tailgate.
Talked to another dealer who mentioned that not a single dealer in Canada got an allocation for a Duramax 1/2ton (Then again, a salesman said it, so take it with a grain of salt)
As far as I know, it STILL doesn't have a build date.
Personally, I doubt you'd see the truck in 6-8mo, and if you do, its because you're taking off options that are on constraint.
I'd take the Blue on on the lot...
Good luck.