I have only seen one other example of the incomplete crosshair on this model which is here (I know my second sweep is broken, working on that!):
https://www.blackbough.co.uk/produc...7-steel-vintage-wristwatch-circa-1968-wwosdb/

This seller labeled it as "Steel Omega Seamaster ‘Special’ Ref. 166.010-67 vintage wristwatch, circa 1968" - the inside case back reads 161.010-67 S.C. - everything else is consistent with my watch as well.
There are a bunch of cosmics from around 1968 that have the same style of incomplete crosshair but I was wondering if anyone had any information on the 'Special' or S.C. aspects of the example.

 

I have been wondering the same thing about the “special” designation. Can anyone shed any light?

Mine arrived today, 1966 ref. 166.010 non chronometer.
Apologies for the crappy photo it’s dark here.

For what it’s worth I think both examples you show above are original dials.
As you say being late models it’s possible they tie in with the Cosmic style.

Edit to add: https://www.omegawatches.com/watch-omega-seamaster-special-st-166-0010

 

That black dial looks awesome! Congrats.

 

Beauty!

 

Bump one time - still wondering about this crosshair! Loving my watch though.