It looks like the US Army also tested the SA342 late in the 70's. I see Kaman mentioned in the test report. Kaman were undertaking a study into fan-in-fin technology at the time and perhaps this is part of their study. They proposed converting an OH-6A with an enlarged tailboom to test the technology. From the drawings I've seen of it, the tailboom would have contained the fan and torque was counteracted by a thruster can on the end of the boom (similar to NOTAR) as opposed to a Fenestron type anti-torque system.
https://apps.dtic.mil/dtic/tr/fulltext/u2/a016921.pdf
500 Fan.