AFAIK, "Thus the current citation for it is
J. Reeds, D. Ritchie, R. Morris, "The Hagelin Cipher Machine (M-209): Cryptanalysis from Ciphertext Alone", unpublished technical memorandum, Bell Laboratories, 1978. Submitted to Cryptologia."
The polite, friendly, retired gentleman could neither confirm or deny that life would get rather difficult if publication proceeded. (ie he wanted to make himself clear without stating directly)
I seldom get that kind of hint. I bet I would have published the damn paper, not because I'd felt it would be my duty as a scientist or citizen, but out of sheer obliviousness to possible consequences.
At the end of the paper there's a specific hint what was behind NSA's non-wilingness to be explicit, at that time, as Crypto AG from Switzerland is mentioned.
Wikipedia has some details about Crypto AG which are a good afterword to the DMR's article:
has been published in 2015:
http://cryptome.org/2015/12/ReedsTheHagelinCipherBellLabs197...