I would think a designation change would be standard operating procedure for a change of jurisdiction.
Even if they go from one sub-state level entity to another?
Sure. We have Clark County 215, and had Lane County's Delta Highway prior to it becoming OR 132.
Unrelated to TM, I would expect the signage to eventually be replaced with something complying with the MUTCD as well.
Like these signs on Orlando city streets?
What is that :lol: