Well, for what it's worth, they rounded the corners a tiny bit on the main view screen of the U.S.S. Lexington
in the re-mastered "The Ultimate Computer."
Compare it to the Enterprise
's main view screen:
Greg, thanks for posting this--really fascinating. I surmise they did this to make it a little more distinctive, so that the viewer would see a definite transition from one bridge to the other (the bridges and ships look identical, except for the high back of the captain's chair on the Lexington). I like it.