The other diver on that catalogue page, the 980.004.. That had an unsigned clasp too. I've had two of them, both unsigned and with no markings at all. So the problem would be verifying a genuine one.
Be careful with sourcing aftermarket oysters, the difficult bit is getting the correct curve on the endlinks. You might find that those designed for a submariner might have a 'tighter' curve, as the big Heuer divers have larger cases than the sub.

I have to say though, the Heuer divers look awesome on oysters.

Stewart

: That would make it easy to get the right look then, with an
: after-market submariner bracelet.

: I imagine the real thing would probably fetch a decent price.