Hi Erik,
I stumbled across this forum today looking for LTN-72 INS pics. I was actually about to create a video on disassembling the LTN-72 Platform.
I have 30+ years experience on the 72 gear. Worked in Defence for 15 years and became the guidance system specialist and then was poached by Litton / Northrop Grumman to work as their guidance specialist based in London for another 15 years.
If you're still looking for info and have any specific questions unanswered I'd be happy to try and help.
Your system has seen better times. Corrosion on the outside and inside. It may have come from a DC10 or equivalent that ditched in a lake somewhere in Africa. I seem to remember pics of the unit that was doing the rounds a couple of decades back. Some second hand dealer was trying to sell it on the open market.
I can see that the platform has never been worked on (has original glue tacks from Litton)