Trying to identify my Omega Seamaster

Hello, I am new to the forum and seeking help about my Omega Seamaster watch, which I bought from a high street jeweller 4 years ago. The store, and a major auction house here in the UK have assured me that it is genuine, and have seen this model before but say it is quite rare. It’s in great condition and the 1020 Cal movement is working fine and the watch keeps really good time. I believe it to be late 1970’s
I am attaching photos for your comments. I have a couple of other Vintage Omegas which are plentiful on the for sale sites, but I haven’t seen another same as mine.
Have you come across this case design before?

Sorry the photos didn’t attach

The number 166.0258 represent the Omega case reference number and as other member told you if you will goole the Omega 166.0258 you will find other watches similar with yours..so everything is ok.

Thanks Mark020, I have checked it out and found the EMMA'S website which confirmed the movement and case confirmation on their database.
I also found images of the same watch too so I am a happy chappy knowing g now that it is genuine and uncommon.

Hi Barb VI
I Found the EMMA'S website which confirmed the movement and case confirmation on their database.
I also found images of the same watch too so I am a happy chappy knowing g now that it is genuine and uncommon.
Many thanks for your help.