I had no idea the 348 was produced in such numbers. That explains why you ALWAYS see them on Ebay. ( I remember around 1981 in Seattle, at 'Amateur Radio Supply', a NIB unused BC-348 for $125. That was too rich for me then, but - - somebody bought it. ) 

If supply vs demand simply applies, the 342/ 344 should have been priced higher. It was not. So there are other factors. The front panel on the 348 is alu, so it's a lot easier to add controls, meter and so on. Some opinions are, it looks better too.

I seem to recall speaking with someone at G&G NYC long ago. The person said they were reimporting them from France and restoring HFO wiring from dual diversity to independent use. I think France used them into the 1960s. I spoke with G&G must have been, 1973. I ordered one 348 and one 342, but nothing, zero transpired and many months later i got a letter asking if i still wanted to place the order, which i did not. Perhaps this was the, or a, period when the owner was out ill.

About this time i got an ARR-15, which was an overlaul and came in a large cardboard barrel. It had been a MARS giveaway. Unfortunately, i semi hacked it. I was pretty ignorant. Still am, i guess, but about different areas now, like eschatology. 

I had one of the France BC-342. Was noteworthy because a front panel marking altho English, was misspelled "DIAL LINGHT".  I recall seeing surplus 342 but not 348 offered in French radio magazines from early 1970s. 

The latest 348 manual i have is TM 11-6920, 1955, and it's just the J, N, P manual reprinted. 

The 342 was certainly used in Korea War and i'm sure i have a photo or 2.

I did not set out at all to gather 348s but i have the BC-224-A and also an R-849 which is K.W. and has the squelch box on top for K.W. radio jeep use with ART-13. 

I prefer the early no - LF band models. The LF band is useless to me and i like the slightly better bandspread. 

Steve Bartkowski many years ago told me he saw a 348 where the LF band had been rewound to tune our AM broadcast band. I don't understand how that could be, without some screeching mess happening. 

-Hue Miller