Are there any signs on the eagle head of a crown being removed? The photo looks as though it was made without a crown? The mounting pins don't look as though they have been damaged to remove the eagle and enable the crown to be filed away? IMO one couldn't remove the crown and not remove the eagle from the enamelled backing. If it was done in situ the enamel and metal surround would be damaged around the eagle's head? Maybe it is just the angle of the photo that doesn't show any evidence of reworking to the badge?
A very nicely sculpted badge from a quality maker!
A more general question: I wonder if any of the names of individual sculptors working for the various jewellers exist?