Sadly, as Joe mentions, this horn would require a bit of left hand work to deal with normal contemporary band and orchestra literature. However, some of these 4V CC tubas play unbelievably well, due to a decrease in weight and a bit less restriction in the valveset. It is of the "good" vintage of 186's. If someone were looking for a starting CC that they would be willing to "upgrade" down the road, this would be a pretty decent buy.
However, I am guessing that the "real" price of adding the 5th in a factory look-alike manner would be a $1500 payment (even though Joe won't say it)

. That puts the horn at about $4K overall, and still an okay price, but no real deal. If this horn were listed with a "buy it now" of $2K, it would be gone. Someone could put the valve and do the cosmetics and get it out on the market for about $3900 and get it sold. While there are no guarantees as to how a tuba plays, you can be pretty certain that a Mirafone 186 CC of this vintage will be a pretty damn decent instrument.