The physical model of the Nebula class actually has surprisingly little that would have been copied from the Galaxy model. The nacelles and nacelle struts appear to be it. The secondary hull is totally different, bulkier in the middle, blunter on the back, with a totally different shape on the deflector dish. The saucer is close, but is missing windows on the lower decks of the upper surface, no impulse engine cutouts, and almost none of the slanted window inserts on the lower surface. Both hulls have a taller band around the middle too. It's not until the CGI model was built for DS9 that it basically became a 'rearranged' Galaxy, and that's what the Eaglemoss models are based on.