Canuck
·Is there any reason why Omega made these cases in both 14k and 18k gold?
Just a cheaper alternative for the buyer or for the better durability in the 14k?
The minimum allowable gold content for jewellery, etc., in some countries was (is still?) 18 karat gold. With the price of gold today, those standards may have changed. But the Omega was from an era when such was the case. Omega produced this watch for export to a country which allowed 14-karat gold. An extract from Omega (if still available) would tell you which country the watch was exported to.

