When my father gave it to me it was engraved, it was given as a 21st birthday present to someone and that's basically what the inscription said. As I recall there was nothing else engraved on the case back. My father said for me to get the engraving filled in and he'd pay for that and that's what happened. At the time it was filled (1998) the watchmaker that filled it valued the watch at £800 for insurance purposes.
I also have a 1965 Omega gold watch and that too has a Dennison case. Must be one of the last produced, as Dennison A.L.D. production ceased in 1967.
This page http://dennisonwatches.com/history/ gives a fair bit of information about the company. They were famous for making cases for companies such as Rolex, Omega and Longines for the British market but it doesn't mention that they were known for collaborating with Bulova. It does say they were a shareholder of Omega.
The link to the very similar watch I gave also shows that watch as having a Dennison's manufactured case, perhaps this was the Bulova strategy during this period, to send the movements only? It would seem that Dennisons were only manufacturers of cases, selling them to manufacturers. Rather than manufacturers of cases, buyers of movements and then sellers of assembled watches under the movement manufacturer's name.
Since 2015 the company has revived and they are now sellers of upmarket watches with cases of their manufacture incorporating ETA automatic mechanical movements.
Fascinating stuff isn't it?