As J white wrote, orange ones are prewar and are somewhat scarce.
I have no idea where the price is.
Variation "F", shown on the web page linked above by Larry, is also difficult to find.
I've actually seen more 154's with orange bases than 154's built with a semaphore base. But the orange based unit is much better known, and more in demand, so they go for a lot more than the semaphore based one.
As far as I am concerned, a restored orange based 154 would be worth no more than a common black based one. (To each their own)