I have one and as far as I know they don't really command a premium over the typical Yugo Mauser.
Bogdanovic says that the BO (unmarked) model 1948s were made in support of the various "National Liberation" movements of the late 1950s.
Since the lack of markings was apparently supposed to conceal their source, and they had an open contract with Egypt and some of the 48A rifles had Egyptian markings, it doesn't make sense that the BO rifles would have been destined for Egypt. However, I've seen many sources on the web indicate that they were made for Egypt so it's hard to say for sure, I guess.
Bogdanovic provides production figures of 386,022 1948BO rifles, all made in 1957.
Mine has the stamped metal triggerguard and came with the typical accessories and one unusual item which appears to be a muzzle protector for cleaning from the muzzle.
They're neat old rifles--it's too bad that 8mm surplus seems to have mostly dried up.