Thanks again for your comments
Here's a view of the rear sight.
Looking at that Steele conversation, and looking at Lyman information, considering the features *including the provision for the flip aperture* this rear sight would be a later first variation.
Further digging around the internet for archived images of early and later Pacific Gun Sight Company catalogs and print media, the catalog illustrations of banded front sight ramps change - and the one on this rifle appears to be their "Improved" model which came around in perhaps the very early 40's
I'll keep poking around, maybe I'll find when/if Pacific either stopped making it with provisions for a hood, or started offering a version without provisions for the hood.