Muddyfox made some great mountain bikes, but the bmx side of things was only to how a presence in the market, just up from supermarket offerings, sold in an era when bmx was pretty much `underground' might be a nicely made bike, but unless you had one as a kid, probably not very desirable in the general market.
GT's and Haro's from the same era would command more money, but still very little compared to old school.
Welcome to RAD anyway.
MM