Would you expect county building code to require a certain height for the "curbing" that appears below the shower stall door?

I would expect the county to require you to follow the IBC. Most counties do not have their own local code but follow the International Building code or plumbing code. Are you building a custom shower pan from scratch? How to Build a Shower Pan (http://www.hoagy.org/house/HowToBuildShowerPan.html)

Here is what the 2006 IRC has to say about that:

P2709.1 Construction. Shower receptors shall have a finished
Curb threshold not less than 1 inch (25 mm) below the sides and
Back of the receptor. The curb shall be not less than 2 inches (51
Mm) and not more than 9 inches (229 mm) deep when measured
From the top of the curb to the top of the drain. The finished
Floor shall slope uniformly toward the drain not less than
1/4 unit vertical in 12 units horizontal (2-percent slope) nor
More than 1/2 inch (13 mm), and floor drains shall be flanged to
Provide a water-tight joint in the floor.