[Hallicrafters] Hallicrafters receiver R -274 GI SX 73?

[greg mijal]

Can someone give me some information on this receiver?  This seems to be
a very rare Hallicrafters
in that I have not seen or heard of  this one beyond the picture in the
Collector guide.
Here's what I know so far:
Circa 1952
Single and Dual conversion
Turret band switch
Rack mount
I am buying one tomorrow from a local gentleman.

Found two references: "Militarized SX 73"  and  "Similar to SP 600"
Sure would like to hear from an experienced person on this one
KKKKK
Greg - WA7LYO
in Sunny Feenix