Checkout this link. Looks like an AA1 type Universal "Midget" meter. The M-7 at the bottom of the indicia suggests that it is one of only nine meters known to be in use during that period:
http://en.wikibooks.org/wiki/Intern...og/Hong_KongI can't comment on the suggested value ($200) as these covers are pretty much worth what a buyer and seller can agree upon, and unfortunately the imprints shown on your example are not particularly sharp, which could diminish its value on the secondary market; on the other hand, the multiple value imprints may offset that.
In any event, it's certainly a very collectible item.