Jim I would say its the rarest of the two, its normally missing from a correct rifle, as they did away with the mag in 1920 (IIRC), so they are either bought as a single item or in most cases sits in a wrong rifle..... its a catch 22 I think, you buy the rifle then wait for the mag to come along or you buy the Mag and wait for the rifle...........

Like you say some don't have a clue what it is or the collector value....