Longines history please

Hi there. I inherited this super watch many years ago. It is very sentimental to me and I just wanted to try to find out how old it is, what model it is etc. Anything of interest. My initial thoughts from my Dad who gave it me is that it is from the 1960's. Thanks in advance.

I think the movement is a Longines 280 or 284, although the lack of a second hand throws me a little. Probably an American made case. The movement is lifted through the front, hence no caseback, and requires a special wrench. If you take it to a watchmaker, they should be able to open it for you. Then you can contact Longines (include photos of the dial, movement, inside and back of the case) and they can give you additional information based upon the serial number.

Maybe it is a cal 428 like here: http://watchtyme.net/longines/ ?