http://www.ebay.com/itm/like/111715348840?lpid=82&chn=ps&ul_noapp=true

I have seen other pieces of jewelry that had SILVER on them but were not even silver plate much less anything else !! I personally think its a selling tactic by cheap jewelry mfrs !! All silverplate is normally marked as such and sterling is ether hallmarked or is marked with purity usually 925 !! The flap as you call it is similar to some of my fishing lures !!
See the clear plastic below the lure above !! Just don`t know what fish yours is supposed to be except maybe prehistoric !!