BudsGunShop.com - Illinois Legal?

No, it is not.

Hi Fred, no sir. Prohibited -
A semiautomatic shotgun that has one or more of the following:
❌ i. a pistol grip or thumbhole stock;
ii. any feature capable of functioning as a protruding grip that can be held by the non-trigger hand;
iii. a folding or thumbhole stock;
iv. a grenade launcher;
❌ v. a fixed magazine with the capacity of more than 5 rounds; or
vi. the capacity to accept a detachable magazine.
budsgunshop.com/feeds/state_reg/illinois_restrictions.pdf

sorry its not even close see shotguns here budsgunshop.com/feeds/state_reg/illinois_restrictions.pdf

Hi Fred and welcome. Unfortunately, no Sir. Due to the Pistol Grip.
A semiautomatic shotgun that has one or more of the following:
i. a pistol grip or thumbhole stock;
ii. any feature capable of functioning as a protruding grip that can be held by the
non-trigger hand;
iii. a folding or thumbhole stock;
iv. a grenade launcher;
v. a fixed magazine with the capacity of more than 5 rounds; or
vi. the capacity to accept a detachable magazine.