I don't have photos, but I've flown CX many times in the early- to mid-80's when I was growing up in Hong Kong.

CX's L1011 have pretty high density seating. 350 seats is about right, as it's 3-4-3 in coach (compared to 2-5-2 for Delta).

In coach, there is towel service, and then meal. But everything's on the tray, just like they are in coach today. If they have different courses served seperately, then it can't be in coach. And I think the Marco Polo Business Class was introduced in the early 80's. So, in 1977/8, there should be only coach and FC.