Should I get some OL2S or lighter tires.

I met a guy today who bought a brand new high lifter rzr today and is pulling off the 29.5 ol2s this friday. Said he would take $600 for all four. I am very tempted as I have been researching a lighter mud tire and 31 ol’s were on my maybe list. Which he has a set for $400 but the tread is worn below the cups in the lugs.only in very center of tire.

I like my 32s , they pull great in mud. But I’m wanting to try a lighter tire and I don’t think the 29.5 ol2s are much lighter then my 32 mudder inlaws. Maybe 6 lbs difference. . Should I try the 29.5 ol2’s out for the price or just buy new 31 ol’s?