Larry,
For all I know, maybe you can see daylight on my Uggie, too. Wood is a natural product, and a stock that fit perfectly 50 or a 100 years past may not fit perfectly anymore. And that includes English guns too. The thing is, I didn't pay for best gun fit of the stock on my gun, and won't care when I'm out in the rain or snow with it, or crash through the ice on a beaver dam I'm crossing (I did that once, and I was carrying a way nicer gun than the Uggie).

The minutia about sidelock pins on the Spanish guns I will happily leave to you guys. In the hard, cold, light of day, I think the boxlock was a pretty good improvement over the sidelock, which, was just a hammer gun with the hammers inside.

Best,
Ted