Various Booklet Pane Lasts

I was thinking about booklet panes and realized there are big gaps in my knowledge of their history.

Which was the last stamp to be issued with water-activated gum in booklet form? Was it #3003, the 1995 Christmas stamp?

What about the last WAG stamp of less than first class rate to be issued in booklet form? Was it #1892 6c circle of stars?

Which was the last stamp design to be issued in panes of 100, coil, and booklet form? Maybe 32c Flag Over Porch?

The last WAG booklet that I could find is BK279/Pane 3377a (A2604-2608 1999 US Navy Submarines).

The last WAG booklet, less than First Class rate, that I could find is BK172/Pane 2483a (A1847 1995 20 Cent Birds Postcard Rate)

Aha, thanks, good finds! That submarines issue made for an unusual booklet. I've never seen a pic of that booklet's cardboard exterior.

Here's the front of the Sub booklet.

Nice, thanks! This subs issue has the feel of being a souvenir booklet.

Definitely a souvenir booklet ... similar to the Old Glory and Lewis & Clark booklets that followed a few years later.

The USPS called the US Navy Submarine issue Prestige Booklets.