Hi Sketchin,
My manual states on page 22: "The aileron servo is mounted on a plastic tray designed to hold just one servo. The tray is in turn screwed to a plywood plate which was glued to the upper center section sheeting. The plywood plate, in this case 3/16" thick, also serves to raise the servo to the perfect height for the small spur wire."

Unfortunately, the plywood plate and plastic tray do not appear to be included with the kit as there is no mention of them in the parts list.

I'm not sure about the manual edition. I could not find any marks clearly denoting the manual edition. The back page does state Sig Mfg, 1987 and to the right of that, "30793."

Interestingly, the plans do not show the plate or tray!

Here is what the picture shows.