Villain 25/17/6 after 130 hands.

Hard to see villan checking back qx, kj, full houses or spades on turn when checked to with spr of 3.
I also block KJ and have the K of spades.

Regs at 25nl are usually underbluffing in these spots which made me fold.
Very suspicious though and interested to know if others think I should be calling with this combo of kk or is villain just not bluffing enough?

Thanks in advance for any feedback.