You could argue for a high and low valuation..

Lets start with 'parts' value.. if these have a signed Movement (I don't know if they do), then a Heuer dial would make it worth market value. Lets say £2-2.5k ish ?

If proved to be genuine, then a mil collector may pay more.. a Heuer collector less, as we don't know where they were built.

I have a gut feeling, that if genuine, and the story is true, then these fall into a military and a 'rare curio' camp.. and could be very valuable.
Some may argue that they have a low value.. but it's down to the individual.

Either way, I look at it this way (if true) - it's a cool looking watch, with an interesting story.. it's NOS, has Heuer connections, has mil connections, is rare..
runs a v72, is unusual as it has a gmt dial.. all this adds up to a cool watch. (if gen)

I just can't see why someone would go to the trouble of making these if they weren't genuine - it doesn't add up.
Far easier to attempt to fake a known Heuer-mil connection, like IDF etc.

PS. Bullitt, is the movement signed?

Stewart
- Heuerville