Thank you for the warm welcomes, StatesmanStamper, Casey Magoo, Stamp Hunting, hoosierboy, and BlackJag!
In response to BlackJag's answers/reply:
(1) SC 1646a
I notice that with this type of paper, it can be easily scratched and can be scratched with your nail. This paper is delicate!
(2) SC 1620a
Those two/three extra bumps are rather dents than bumps. If you look at the back side of the stamps, you'll see the three bumps like the bumps used for Braille. I happen to have a few sheets of a different stamp like this. What is this phenomenon called and is there extra value when this production error happens? It's kind of a funny one!
(3) BK 265
I forgot to circle that in my original picture - apologies for that. I've taken some new pictures - it can be seen here. Funny enough, I'm seeing this phenomenon also occur on another one that was recently sold on eBay
item # 154427474987
). Have you guys seen this occur with stamp booklets before? I've tried to flatten it out with weights but no luck - looks like it's going to be there for good!