Maker of this pierced plate?

[curiousbob]

I did see a similar mark in another post, but there seemed to be a number of different responses (keystone, forbes (but which one?),etc), but I thought I would try my luck anyway. the first mark looks like a heraldic "F", the second is definitely a "S", not sure of the third (maybe a "R" or "I"?) and an eagle head. Thanks in adavance - curious bob

[wev]

Forbes.