I think the problem with a sample size of two is it doesn't really help us come down either side of original modification made for the watch or refinished by the seller. Potentially even a change on behalf of one pilot that caught on with the others. And looking around, it does seem to be largely Arno's watch and more recently this one, would be nice to unearth more.

The watch kind of comes between a number of custom watches for commercial entities (Volvo and MG as well as the Indy circuit), where Heuer's involvement was largely agreeing the addition of the company logo with the dial work being done by the dial supplier, and the wholesale modifications they made for the Belgian military watch. If the Belgian Congo watch came with second markings too, it would make our job a lot easier, but that has the usual 1/5 of a second, albeit in black.

Applying a logo to the dial is a bit of an easier decision, especially when greased by some helpful cash from the customer (!), than amending something that was iconic for the Carrera and played on in advertising. There must have been some sort of exclusivity agreement with the Bundeswehr for a while, as Heuer don't seem to be directing military customers to that watch - the Norwegian AF Bunds come later on.

So I think I'm kind of reserving judgement unless/until we see more examples and putting out the possibility that the bezel is refinished. I think we can agree that the end price is a bargain compared to the less nice example at Arno's auction though!