I got this thing here because someone requested it (thank you for that as well!) so here you go!
How to Install: Open up the .zip file. Inside you will find a file called zClassicShotgun.gro. Copy it to X:\Program Files\Serious Sam 2 (Meaning the root folder of the game) Start the game up and enjoy your classic cannon!
List of Features:
Stats edited to be true to the original Serious Sam
New Animations (They aren't spiced up so they look pretty static (sorry for that) )
Devostator - Converted the model from SSTSE then improved it, adding texture to it
Croteam - For creating the weapon and it's sounds
Pablo-- - Making the animations work, converted sounds, Weapon's placement in first-person and more improvements which I forgot
(THE MODEL WAS CONVERTED FROM SSTSE!)
(P.S: This shotgun model can be improved by anyone who wants to do the task. Just don't forget to credit the people who made it first!)