That is a very cool looking set!
UHF tuner addons were fairly common modifications here in the early days, though adding a seperate UHF converter was more common. the bakelite box on in this picture is an example of a UHF converter box.
I use photo bucket to host my pictures as they give an IMG code listed below my pictures that I can copy-paste in to my posts so the picture will appear in my post. Here is a link to my album if you are curious...
http://s1095.photobucket.com/albums/...ory/?start=all