Do the colour blind have a distinct visual cortex structure?
Interesting question! I performed a fairly extensive search in Google Scholar and Scopus using various keyword searches, including, but not limited to "color blindness and plasticity", "color blind and brain", "dichromates brain", and "monochromates brain". Strikingly, I found nothing. The reason is aptly explained by Solomon &amp; Rosa, 2014 and I quote from their interesting review:


  As yet no anatomical correlates of color blindness have been found in the retina (Chan and Grünert,1998; Chan et al.,2001; Jusuf et al.,2006a,b), thalamus, or primary visual cortex (Goodchild and Martin,1998; Solomon, 2002). 


If desirable, you should be able to re-trace the relevant citations from the cited review, as it is open source.