Here is a typical Jeffery 'Moon Sight', in this case on Norm C_'s .333 Flanged with 'Prowling Tigers' engraving. It's almost identical with mine, only difference is the ivory main bead.

Actually, this one sits a little proud, they should be flush when folded down, needing a fingernail to lift into position. I'll photograph mine in the up and down positions when time permits.