Did you happen to notice the bolt through the head of the stock?

I don’t see evidence of reproof, either. I’m having a hard time believing the proof house would accept an older 2 1/2” boxlock for steel shot reproof. Or, that they would fail to mark a gun that had been subjected to that.

The world is awash in older, English 12 gauge boxlocks at the moment. I’ll go out on a limb and guess very few, or, none of them have been reproofed for steel shot.

Best,
Ted