Alright, I did some digging though the stash. I have one of these that was used as a shop display that still works and a couple that are for parts. The display one is S&G from 1995, 2 others are S&G that are much older, and one is a Lagard 3330 with time delay. For the newer S&G ones the correct change key is "U10".
The older S&Gs can only be set for 15, 20, 25, or 30 minute delays while the newer S&G can be set from 5-30 minutes. The newer one also has different modifications to the lever, it has 2 pins instead of 1 in the older models.
The 3 "parts" units
The Lagard unit
Mounted to the lock
On the left side you can see the screws to set the time delay. On the bottom one there is a piece broken off on the middle bottom
One has a clear window so you can see it working
Here you can see where there are pins added to the lever and drive cam
Now for the new one.
There are different modifications to the new lock since they use a different movement in the time delay. There are 2 different pins in the lever and the one in the drive cam is placed differently.
The movement. The drive cam pin latches into the hook on the right and the dial winds the movement. Once it gets enough tension the hook pops open and releases the pin. You can see the adjustments for the time delay are quite different as well. IIRC the 2 pins on the lever interact with the part on the right. It blocks the lock until the correct time has elapsed (and POSSIBLY) resets the timer if you try to open it too early. I may be wrong about the last part.