probably far more in Europe...How many 4+2 Symphonies are out there?
When places such as **Giardinelli et all were importing them (new), features such as "a sixth valve" or "gold brass cost an extra $50 or so per feature. I suspect they preferred to pay only $500 (vs. $550 or $600) to buy them from B&S, because Americans would buy them with or without the upscale (6th valve or gold brass) features.
My 6-valve (yellow brass) was brought to me by a full-time orchestra tuba player who lived in Berlin. They bought this particular one, because that was what they found in stock (wherever they found it - over there). They did ask me, "Do you mind if it has six valves?'
They charged me (later - 1982) $2400. That covered their intranational (within German) r/t transportation to go buy the tuba, their r/t multi-stop plane transportation from Berlin to *Baltimore (where I drove to pick it up from his parents after he returned home), so that HE COULD VISIT HIS PARENTS VIA THE PROFIT FROM SELLING ME MY TUBA, and - also - some walking-around money for his trip, as well as (surely) some money to buy some stuff for his parents (who - it appeared to me - when I picked the tuba up - lived in an extremely modest house...and I did NOT see an automobile parked outside it, either). For all I know, he may have bought it directly from B&S - as he could have acquired a special passport to enter into the GDR. (Berlin and Markneukirchen are only about 200 miles apart - as the crow flies.)
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*My brother - to this day - lives in Arlington, VA, so my brother picked up that tuba player at the airport, and drove him (and my tuba) to his parents' house in Baltimore...(logistics) He got it through customs without paying duty. The T.U.B.A. Conference (right near there at the University of Maryland) was only a week later, so he told them that he brought "his" tuba to perform there (which was a lie...He flew back home before it began). My brother watched the tuba player (who suffered from mood disorder) schmooze it through customs, and my brother was quite proud of the tuba player, as it was a stressful situation.
**Roger Bobo had told me that I could buy one (from the place linked below) in Washington state (though I had NOT seen Bobo play his on the Tonight Show, but HEARD one played LIVE by the Leipzig Gewandhaus Orchestra, and noticed that the Leipzig Orchestra's tuba player - an old out-of-shape fat man - was being heard (and sounded good) playing one on Tchaik 5), but I never reached out to this store in regards to buying a B&S tuba: https://www.kennellykeysmusic.com . I suspect (??) that Mr. Bobo bought his from them.
When "Mr. P" began having the Detroit-area music store import them (with the mouthpipe and bore sizes goofed up), that's when the bargain pricing (and the amazing playing characteristics) were shot to hell (with apologies to Mr. P for expressing my opinions here, but he DID hear me play mine in an "Oktubafest" recital and ran around to the stage door to compliment me...so he must have heard something-or-other "good" in the unadulterated "Symphonie" Modell that I was using). One thing that SOME people probably do NOT know is that the original-original-original versions of these featured a SMALL (bass trombone size) receiver, which explains why the choke point (smallest dimension of the mouthpipe tube on the ACTUAL Symphonie F - even when the began making them "standard" shank) is only around .500". This is a dimension that even Eastman didn't have the courage to copy, which is one reason why they STILL don't QUITE PLAY LIKE genuine Symphonie Modell F tuba...and (again...) I tend to wonder about that dimension on the ZO version (which I judged to play better than the Eastman version).