[Genome] light blue vs. dark blue in UCSC genes

[Ben Berman]

In the new UCSC genes tracks, is there a way to programatically  
distinguish light blue from dark blue (using information from  
knownGene, kgXref, or other tables)?  I am not exactly clear on the  
criteria which distinguish these two classes.  For instance, here's  
an example of a transcript that has a protein ID but appears light  
blue (uc002pto.1):

http://genome.cse.ucsc.edu/cgi-bin/hgGene?hgg_gene=uc002pto. 
1&hgg_prot=Q6ISI0&hgg_chrom=chr19&hgg_start=56020356&hgg_end=56026591&hg 
g_type=knownGene&db=hg18&hgsid=94386256

Thanks,
ben.