While the second gen does fit, it is not perfect. The angle of the spring perches between first and second gen is off by a few degrees. You can force it to bolt up, but this puts stress on the springs and shackles. A better way is to cut the perches and re-weld them properly. I know because I have a 1979 disc brake rear in my 1968 convertible. We cut the mounting perches from the axle tubes, then lowered the car down so we could see where the spring perches rested on the '79 axle. It was off by a small amount. Then we tack welded the perches in place, removed the axle, and did a proper job of welding the perches permanently. At the same time we added the brackets for a set of 1967 dual traction bars.

The second gen rear is a Chevy C-clip type rear vs the BOP rear. You will definitely need either a Chevy yoke on the driveshaft, or that dual Chevy/BOP U-joint I mentioned. I believe Lakewood made it.