Sorry that's happening to you, Bruce. I just thought you might have missed that post.
I cleared out all my D&H books except for Jim Shaughnessy's.
He lists all the diesels up to the U 30-C but no mention of phases, just build dates.
I checked in the text and could no mention either. It did state that some of the RS 3s were rebuilt in the late 50s early 60s.
Sorry I couldn't be more help.
Greg O.