Tim,
there was an article in one of their clippers, back a few issues now -->
http://www.guilfordrail.com/xpress/2009q4.pdf <--, that said that they were rebuilding/overhauling locomotives and then painting them dip blue. I'm sure thats what P42 was referring to. The issue is almost 2 years old, so I don't know if the practice still holds true today.
Quite an interesting article, now that I'm completely OT, thats talks about how they actually purchased remanufactured parts and had everything lined up before hand so the unit would only be down long enough to swap out engine blocks. Says that units will be put in service for 30 days to essentially test the rebuild, and then will be repainted dip-blue.
Back on topic...Based on that, I would say no overhaul for the 77, since it went to the shop and never served 30 days testing before being painted...
Oh, and ditto on the new picture, its pretty sweet R.T.!