I think you're confusing currency and commemorative coins. With the former there is no secrecy - the published figures before 1953 are for coins minted in a given year whatever date was on them (I believe 1953 was the year it changed, Mike?). As for dealers, their interest is to preserve the status quo not stir things up.
With commems, the situation is reversed. The RM uses perceived scarcity to sell its issues so sometimes it pays to conceal the actual figures.