[R-390] Rare R-390 radios

[Paul H. Anderson]

Here's the radios that I've heard of that are rare (and exist):

Folwer radios (all five)

prototype radios (they have X or PP in the tag ID #? and sometimes other 
indications of handwork - I think there have been at least a few sold on 
ebay)

The two R-391A's (one apparently complete, one missing some of the 
autotune mechanism - this one sold on eBay awhile ago)

If there were documented #1 radios, I suppose they'd be rare.

What else out there is truly rare (and exist)?

Paul