When it comes to dating of KISS pics there is truly exceptional work being done in fan circles to try and establish a working chronology, but even when the dates are more or less known it's never perfectly certain. Case in point, the removal of the original strap button on the Firebird I. As seen in the 1964 catalog listing of the Firebird I (right) the strap button was located on the upper bout (also seen on this beautiful 1963 model). Judging by the vintage 1963-65 Firebird I's for sale at the time of writing moving the strap button was a fairly common modification, one that Clapton had done to his Firebird I during the Blind Faith "era", because the original placement had the strap twisting and turning which meant that it was never truly securly fastened. For a band like KISS with their energetic stage show and vigorous movement on stage, this probably caused a real problem and the strap button was simply moved to the back of the neck heel.
The issues of pic dating comes to the fore with the first good pics of the Firebird I in Paul's hands which are from Detroit, MI. The band played two shows at the Michigan Palace on December 20 and 21 of 1974 and although we have pics that are supposedly from those shows nobody really knows if they're from the 20th, the 21st, or both. Assuming the pics presented here are both from the shows at the Michigan Palace which has been claimed, we can sassume that Paul's tech first installed a new strap button on the back of the heel on the 20th and then removed the superfluous strap button. The pic on the left shows the original strap button still in place but not being used; the strap clearly attaches to the heel of the neck; the photo below, which has also been claimed to be from Detroit, doesn't show the strap button and Paul has a different choker. (At least my eyes can't spot it even though Paul elaborate belt kind of complicates things.) However, three days later in Wilkes-Barre, PA the strap button is still there.
[Right] Excerpt from the 1964 Gibson catalog showing the starp button placement on the Firebird I. Catalog scan courtsey of Vintage Guitars.
[Left] Firebird I in Detroit, MI with the original strap button (albeit unused). Click to see enlarged detail.
So, if the photo on the right isn't from Detroit, MI in December, when is it from? When we enter 1975 Paul seems to favor the Midnight Special and the Firebird doesn't really show itself until San Fransisco, CA on January 31. Judging by the video from that show it seems as if the superfluous strap button is still there which might mean that it wasn't finally removed until the Firebird was re-finished black.