Why not? It's a pretty bad idea to show up at the line on equipment you've never used before. This is why you sometimes train on your race rig (if you have more than one bike), your TT rig, hell even your carbon race wheels.
So then why not train in your skinsuit? From wearing mine, I've noticed that the feel is different and that definitely has a mental effect to it. So why not train in it to acclimate myself to the differences?