u/DeltaZ3ro

Hi All. I’m attempting to remove this old Kodiak bait well but when I try to unscrew the 4 bolts securing it to the deck they just spin in place. Should I just cut the heads of the bolts off? Or is there a less invasive method that I’m not seeing? This boat is new to me so I don’t know how it’s mounted underneath the tank. Thank you!

At first I thought it was a copper based on my chart but now I’m thinking brown.