I think that's the first time I've seen a
gold Calibre 12 with the 12 in the little blanking pit - it's almost always the case the case that it's on the silver coloured bridges used in the earliest Cal 12s.
My assumption was that the bridges had originally been stamped with an 11, but that was blanked and 12 stamped in the resultant pit. I still think that was what happened, but then why do we have a gold bridge that has been through the process?
Were they thinking of adopting the gold bridge for the late Cal 11s, or as a way of distinguishing 11i from earlier 11? Were some of the Cal 12 bridges initially stamped 11 by mistake?
Jeff, this probably has some implications for your intended page, it may need some further digging...