Some of those photos were published in a Trek book that covered the scripts and making of the pre-TMP/aborted TV series. And there are some photos of it in the Brick Price book that is featured over at star-art's site.
I think the jist of it goes like this - New TV series begin development over at Paramount in '75 or '76. Don Loos begins working on model of ship based on Matt Jefferies' redesign. That incarnation is abandoned when it is desided to make Trek into a feature ('77/'78). Matt Jefferies has also left the project by then. Richard Taylor and Andy Probert begin a new redesign where the Don Loos model left off. Similar in shape but with different details. The 100" refit Enterprise also went through some revisions during its construction - notably the bridge cap and the cap on the underside of the saucer. I've seen shots of the top of the saucer and at some point, they changed out the bridge from one that greatly resembled the teardrop shape of the TOS Enterprise bridge to the one we know now. I have comparison drawings somewhere that show the refit and the TOS version and you can see the differences since they were done during the design/construction phase and not after the fact like the blueprint set that was commercially available.
At least that's what I've been able to piece together.
Gene