The "hook" feature of Paul's no. 1 Flying V during the Spirit of '76 Tour is such an easy-to-miss detail, much like the hairline crack in the mirror pickguard, that I think it requires a small section of its own. Truth be told, this is a detail I had completely missed myself, both the hook itself and its use, until it was pointed out to me by Ros Radley of MAGIC - KISS Kronicles 1973 to 1983. Case in point, I'm willing to bet that most people perusing this site didn't see the hook in the photo on the right when it was used to illustrate the hairline crack in the mirror pickguard.

The "hook" in question is an Omega-shaped metal hook attached to the upper part of the body a little below the neck. It's not visible in any photos from the European tour earlier in the year and is doesn't appear in the photo shoot on June 24. In other words, this is a feature that was added specifically for the Spirit of '76 Tour and although it might have been added before the tour the first photo that shows it that I've been able to find is from Toledo, OH on June 31 as shown in the two pics on the right. It is however, as mentioned below, apparent in Jersey City, NJ on July 10. (I've taken the liberty of circling the hook in all the pics since it's so hard to find.)

Now, this doesn't necessarily mean anything since the hook is mostly "invisible" due to Paul's costume at the time; the rhinestone-covered crotch of Paul's Destroyer costume tends to make the hook disappear in photos taken directly from the front as seen here, and since it is in use early in the tour it's very likely that it's present at the very start as well.
[Left] The backstage photo from Houston, TX on August 13 shows the no. 1 with the hook very clearly. As a bonus we also get to see the "hook-less" no. 2.
That leaves only one question: what was it for? For one reason or other Paul occasionally used the hook to hang the V from the mic stand at the end of Firehouse. I say occasionally because although this use is shown very clearly in the video from Roosevelt Stadium on July 10 he doesn't use it in that capacity in Anaheim, CA on August 20. There are also precious few pics that actually show its use. When in use, Paul "un-shoulders" the guitar and plays it while hanging from the mic stand for the final chorus. He then steps back while the guitar resonates the open A-string, presumably to move out of the way as Gene breathes fire. Since the focus of the show at that time is Gene breathing fire it's hardly surprising that the "levitating V" has been caught by photographers so rarely.

One shot is from Richmond, VA on July 8 as seen below. At first glance this might seem to just show Gene breathing fire (with the singularly awsome rubber tree in the foreground) but on the far left in the pic are the wings of the Flying V. Look closely and you can see the strap hanging down from the guitar. As anyone who has ever strapped on a Flying V can attest, the center of the body of the guitar ends up at the center of your body and in the pic below Paul's body is nowhere to be seen. The guitar is just hanging from the mic stand and resonating.
The only other photo of this "effect" that I've seen is a still from Jersey City on July 10 (as identified in a Japanese magazine). The color photo below, despite the less than stellar quality, show the Flying V on the mic stand with Paul a few steps back watching Gene. (Unless Paul suddenly developed some serious contortionist skills at the time there's no way he could have his head in that position if the guitar was hanging from his shoulder.)

I would argue that the visual effect of the "levitating V" was, quite frankly, almost meaningless since the focus during that part of the show is so intently on Gene breathing fire. It is nothing more than a side show, one that most people would have missed in the live setting. Couple that with the only occasional use (even if it may have been more wide-spread than we know based on photo evidence) and the "levitating V" not surviving past the summer is hardly surprising. Once the band embarks on the Winter Tour in November of 1976 the feature is gone and never seen again.

[Right] The "levitating V" in action in one of very few photos ever taken of this part of the KISS show. Gene breathes fire in Richmond, VA.