Take one of the lifters apart. If there's a plunger that moves up and down and a spring in the bottom, it's hydraulic. If the plunger sits on a ledge and does not move up and down, it's a solid. Do not use solid lifters on a hydraulic cam and do not use hydraulic lifters on a solid cam. If there's any, I repeat ANY doubt in your mind about the condition of the cam, if all the lobes don't check out within a couple of thousandths of each other, junk it and start with a new cam. Cams are not that expensive and it'll break your heart to get it running and then wipe a lobe and have to tear it down to clean up the mess in the motor. When you can buy a new cam for less than a hundred bucks, it's just doesn't make any sense to start with a less-than-perfect grind.