Any list of Omega models made in a particular year?

Anyone know if there's a list of the different models of Omega that would have been available for sale in Ireland/London during the late 70's?

As a toddler I buried an Omega that my father had gotten as an engagement present from my mother on Curracloe Beach and have often thought it would be a cool present to manage to get him the same model again (i.e. repay him for my actions as a 2 year old!). My parents have divorced quite a while back and even if I did want to ask her I doubt my mother would be able to tell me which model it was. Thinking if I could narrow the field, a browse through old photo albums might help me identify the model? Or would they have had that many models available in 77/78?