Yep, based on closer examination of the saucer section and nacelles, I would even guess that they used the original 1980 David Kimble TMP blueprints as templates for those parts before tacking on the rest of Reliant's superstructure. They look pretty much identical in details and proportion. I used that very same technique some 35-38 years ago when I did my own hand-drawn schematics, back before the days of easy-to-use vector art systems.