Where can I get the correct replacement emissions decal?

Well, demonsizzler says it's time to rebuild the ThermoQuad on the 440 in my '78 Dodge D-300 dually, so I thought I'd do an engine compartment refresh at the same time (remove and paint the intake manifold and valve covers; clean out the choke heat passage in the right cylinder head; etc.). I was able to obtain a rattle can of the correct Chrysler turquoise engine enamel, and I thought it would be cool if I could also obtain the correct emissions decal for the valve cover. I've seen the various websites that sell the common hi-po emissions decals, but this truck doesn't have a common one because it's a California "heavy duty cycle" low-compression 440. Does anyone know where such uncommon emissions decals can be obtained?

Thanks!