This may end up being a party of 2, George, as I'm not sure there are many lefty BC Rich owners here. (Though I have a faint recollection that Carmine has a rare Gunslinger bass).
Yes, the Rico period BC Richs are very rare, and I concur with you on the quality. These are high end, hand made boutique instruments that easily rival the Ken Smith's/Sadowsky's/etc. made today. Possibly THE most comfortable necks I've ever played. Quirky (overkill?) electronics only add to the unique appeal, IMO.
I still own 2 Rico period Rich's, my 1977 Bodine/Eagle bass and my 1979 TJ Mockingbird (longer horn than George's "short" horn version pictured above). Both were purchased from Tom Tyner/Lefty Loser Guitars, a huge BC Rich aficionado, who also had a lefty Wave bass for sale at one time.
The Eagle bass is my favorite BC Rich, being the most accessible in appearance and the best in balance and comfort. (Not being a Heavy Metal musician, I personally never cared for the crazier pointy designs of BC Rich's other models). Bernard Edwards of Chic played one, so that should be proof that BC Rich wasn't exclusive to Metal. The Mockingbird is a classic design too, but admittedly they don't balance very well.
George, are you keeping the Barts in or did you since install the Dimarzios?
FYI, Adirondack Guitars has a 1981 Rico period 8 string Rico Supreme Bass for sale now. Very tempting:
http://www.adirondackguitar.com/lefty/used/14/bcr_8.htm