Since there is absolutely no documentation that any 67 Lemans stripes were applied by SA, I'd think that they are all "day 2" items.
There were some very active "Shelby" new car dealers that were always attempting to promote the cars.
Very early applications of the stripes likely is attributed to some of those dealers.
Now my 67 is an original Gotham Ford card. I found the original owner and discussed the car.
In my case, when I got it, it had a "copy" of the "Supersnake" stripes. I specifically asked him about it.
He said that, he was from Brooklyn when he bought it and enrolled in the LA School of Automotive design soon after and drove the car to LA.
While he was there, there was a flash flood the car was in. He had Allstate Ins, and they refused to total the car and took it to Mel Burns Ford to have it repaired.
Now get this, while it was being repaired, they installed "GT40 seats" (which absolutely no one on this planet knows WTF he is talking about because they have never seen or even heard of them), installed a 427 to replace the flood damaged 428 AND had the stripes painted on the car.
So, I have to just note that information and acknowledge that there are a lot of snowflakes, too many in my view, that when the sun comes out, melt away and disappear?
But the short answer in my case (even though they aren't Lemans stripes but are 'Supersnake stripes, sorry for that) they are "day 2 - original owner installed.
Typically, there just are no easy, yes and no answers and simple boxes to check? Everyone seems to have a story and those that don't, seemingly the story just hasn't been documented yet? That's just they way it is. After all, they are genuine "Shelby's" and since when did those EVER fall into a "cookie cutter" designation? Maybe never?
Incidentally, Gotham in 67 sold more Shelbys then anyone else. I have never heard of any owner claiming that their car was purchased new from Gotham with stripes. Period.
I will also point out that you would have HAD to have bought it from Bill Kolb, and if it meant painting stripes on his mother to sell it to you, he would have.
Ask Howard how Kolb wouldn't let him leave until he bought the '65 at Larsen? They all but locked him in the room.
OH! Bartell did a poster called "Turn 2" which depicts a '67 in a race and it has Lemans stripes on it. That was seen in magazines like Popular Mechanics, but not limited to it, and had to have been influential at the time?