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From the first photo it looks like it did have an "N" number at one time.
Who knows! He seems to be gathering quite a collection over there.
Looks like this C-47 was used for ELINT (Electronic Intelligence). One, maybe more of the C-47s that the Israelis acquired was set up for ELINT. These were called Barvaz, or mallard in English. I am still gathering, but this plane was built in 1943 and sent to Europe. After the war, the Belgians and the French had it for some time before going to the Israelis in approximately January of 1967.