Early, early Maltby? One of the first??

[Lance]

Here is the backsight area. While taking photos I noticed there appears to be a pilot hole that was filled by the bolt head release, it could be just the design of the milling bit also?

I also took a couple more pictures of the markings/blue finish as the first one was dark. It is hard to photograph as it either bleeds out the color or looks overly dark.
.