wynonie,
These were on the very late 2000 series... (possibly others)

From 84 catalogue..

Stewart

: This is a pic of a strap and buckle I've put together from two
: separate ebay purchases. I wondered what the experts thought
: about the authenticity of both/either pieces.

: The strap is unused, 20mm lug width but only 14mm at the buckle.
: The material is a very thin leather (possibly corfam, but even
: thinner than the NOS corfam straps sold by Squinky). There is no
: other marking apart from the 'Heuer' gold shield.

: The buckle is clearly old, and there is no other marking other than
: the 'Heuer' shield - ie no sun or inox on the reverse. I'd never
: seen one in this style before, but thought i'd pick it up as I
: can't believe there is a market for fake 14mm Heuer buckles- and
: I needed a 14mm buckle for this strap.

: I guess its easy enough to fake the strap and find a mug like me to
: buy it, but now I've found a 14mm buckle which i'm inclinced to
: trust I'm hoping it may be authentic. I'd welcome any thoughts
: from the forum....