Not necessarily- some enamels intended for 1:1 automotive use could still contain thinners hotter than a hobby lacquer can withstand. Does Scale Finishes recommend a specific primer for use with their paints? Failing direction from the paint supplier, a good automotive lacquer-based primer (Duplicolor, Plastikote) would likely hold up well. Spray some test panels on a junk body with mist coats and a wet coat to see if that sorts things out.
Lacquer paints work in a specific way- they mechanically bond to the previous coat (be it the primer, or another color coat) by melting the previous coat. It looks like your wet coat was a little too hot, and that melted the primer and the plastic underneath as you waited for the solvent to gas off, allowing the grain of the bare plastic as-molded to show through into your colour coat. You could strip it and start from scratch, you could sand it and re-apply primer, or you could sand the color coat and mist on a few more light coats on top and let them cure, and then hit it with a few more mist coats plus a wet coat that hopefully won't bit into the previous coats and bring the grain of the plastic through to the surface again. Was your primer compatible with the top coat you used?
I've wanted one of those forever- was looking at one on modelroundup.com (Hendrix Manufacturing IIRC) but something looked a little "off", including the price tag . Checked Morgan Automotive Detail's site and didn't see it listed.
If you want the first ones in styrene, they were included in the "Hot Rod" boxed version of the Revell Model A pickup- minus the spinners. http://i.ebayimg.com/images/g/k1IAAOSw241YUt-u/s-l300.jpg That was a dark time for Revell- quality of parts and chrome was pretty bad, but with some clean up might serve as a "roll your own" resin master.