Yes, the Evolution Gun Works Picatinny Scope Mount is made in the USA.
Im not sure if this will fit your gun. Optics Planet should have the hole spacing measurements listed out in the secondary pictures for this base (if not we have them listed on our site), please compare those to the spacings on your gun to verify fitment.
No, the receiver on the Shockwave is not drilled and tapped.
It will not work as it fits models post 1997.
No, it will not.
The manufacturer, EGW, describes the 45310 as
Mossberg 500, 590, 835, 930, 935 Late (after '97) Shotgun Picatinny Rail Mount Ambidextrous
Product #: 45310
The manufacturer describes the 45300
Mossberg 500, 590 Early (pre '97) Shotgun Picatinny Rail Mount
Product #: 45300
It would appear that with a 1996, you would use the pre-97, 45300.
Thanks for pointing out the error on the webpage.
Mark H.