My furnace and kitchen sink are next to the dry shower.
The cord plugged into the blue box goes to the silver box behind the electrical panel. The other silver box by the vertical board is a 4x4 4-wire electrical socket fed by the generator. I do not have a transfer switch and plug into the generator when not plugged into shore power.

https://www.dropbox.com/s/fylwe5hu48chqu2/20171007_225426.jpg?dl=0
I opened the breaker box and was surprised to see the red leg was not connected to anything. When I got the coach all these breakers were on. I was thinking of installing 50 amp 240-volt shore power box next to my parking pad. One of the left breakers was labeled rear AC. The rear AC unit had been removed. I am guessing the black wire in the lower left goes to the rear AC unit. The other item is the white wire jumping from the right buss bar to the center buss bar one location left of the green wire. Bet if I removed that white wire my GFI would not trip anymore.

https://www.dropbox.com/s/7t9bnl6qzlgq7ta/20171007_163204.jpg?dl=0
The left breaker is the black leg input followed by the outlets, the blue box which supplies power to the silver box behind the breaker box and the 15 amp breaker controls the front AC unit. https://www.dropbox.com/s/tulb0ebrejmjnn4/20171007_230541.jpg?dl=0
I am pulling the breaker box forward to find what is behind it.
https://www.dropbox.com/s/tulb0ebrejmjnn4/20171007_230541.jpg?dl=0
Here is the label from the silver box behind the breaker box.
https://www.dropbox.com/s/oglr1mkwu49o77z/20171007_230557.jpg?dl=0
Is this a new upgrade for the famous buzz box?
Is there a problem using the dash switch to link the house and chassis batteries together while on shore power to keep the chassis battery charged?

As I understand it GMC did not build any trans modes until 75. I do know the serial numbers started over with 100,000 every year.
Not sure if the serial numbers for trans mode are interlaced with GMC completed units or if they had their own set starting with 100,000 each year.
There is only 1 unit between your's which may indicate that they were building trans modes that day or that the trans modes had there own set of serial numbers. We also have to take into account that this is the model year which starts in the late summer rather than the actual build year. To have 425 units built by November they are probably sharing a common serial number sequence.

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*John Phillips*