From an on-line discussion of the wooden device you have seeen:
This is actaully a bit odd. IIRC both the Panzer IV, Panther and Tiger I & II had internal travel locks for the gun and the Panther was the only one to have a fixed, external lock as well (why?). Why would the Tiger II need a removable, external travel lock like the one apparently seen on the photo?
All pictures I can recall of Tiger IIs travelling either by road or by rail does not show this device in use and I've looked at a bunch of Tiger II pictures and only this one actually shows the device - and only on some of the tanks. If it was something you would commonly use, then one would think you'd see it in use more often?
Looking at Tiger IIs travelling on the road or on rail-cars, it would seem, that once the internal lock was engaged, the weapon would be in a rather elevated position, as you can see on the first picture. My guess would be, that in some cases, you would need the gun to rest in a lowered position and in order not to damage the elevation gears, a temporary rest would be used like in the attached picture.
Anyway, I came across one picture which appears to show something like this "gun lock" (perhaps rather a gun rest) in use. It seems to be resting on the ball mount, supporting the gun.