It's not more valuable, but in terms of rareness as a separate trait for a given coin, individual
fourrees are generally rarer than the solid coins they copy; if a
fourree isn't
rare because many
fourrees exist, you may as well say a non-plated
Labienus isn't
rare because lots of
denarii exist. I personally am searching for some specific
fourrees that I've
had trouble coming across; I
had good luck finding lots of clearly
fourree examples of quinarii, but have yet to buy any undisputably
plated dioscuri quinarii (I have some possibles, but I'm hesitant to clean certain spots enough to confirm.)