[GreenKeys] History question - Model 26 in military service?

[jhhaynes at earthlink.net]

Now I had always assumed that production of the Model 26 ceased
at the onset of WW-II at the latest, and then production of spare
parts ceased in the mid 1950s when lots of the machines started
to be available to hams.

The RSGB Teleprinter Handbook by Goacher and Denny, 1st edition,
has a small section on American machines and shows a military
TT-4 which is plainly a Model 26 mechanism in a military housing.
Another picture of a TT-4 is the Kleinschmidt machine well known
as a TT-4.  So I'm wondering if Teletype made some Model 26 machinery
for the military, possibly as a trial model competing against the
Kleinschmidt, and then didn't get a contract or wasn't interested
in getting a contract.