Per Robert Frederick:

When the order is punched in, it goes to BA Status which means order received.

Then it will move to BX if its a good order available for schedule.

A BX order can then move to C Status which is tentative schedule.

Then it can become D Status which is Firm Schedule at which point a serial number is assigned.
Next is D1 which is Gatelined which means the plant has sequenced the order for production and an estimated ship date is assigned.
Build codes then follow:

E is Framing
F is Paint
G is Trim

The unit is built at this point and goes to I which is final inspection.

J is unit passed final inspection

JB in the case of Challenger, unit is shipped to Upfit Center(For stripe).

KZ means unit released by plant and Invoiced.

KZR Vehicle within a few days of Dealer. Don't usually see this code though.

From KZ it usually takes a few days to a week or so to get to dealer.