[Milsurplus] ? re FRR-23

[Hue Miller]

Epay recently had a Navy AN/FRR-23 receiver:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2175677737&category=586&rd=1

This looks exactly like an SRR-21 but with an FRR-23 nameplate
instead.
However, the manual for the receiver series, shows  the  FRR-*
equivalents with green, corrugated cases, resembling the GRC/VRC fm
epuipment cases, not the smooth grey cases of the shipboard SRR 
receivers.
Comment, anyone?
Tnx, Hue Miller