Cab Lights Question W or W/O CA Emissions

[esbstuff]

I called the dealer today to order some new cab lights (5 clearance lights on the top of the cab) for a 87 1 ton. The dealer asked me "With or without California Emissions?" What the ??? After a short discussion, he was serious.

So my question is why and what are the differance in the 5 clearance lights between federal and CA emissions trucks?

BTW the CA lights have been discontunied... The others were $13 (retail) something each. I also ordered 5 new gaskets and they were $3 each.