All motor oils are backwards compatible so current SJ oil will perform the same/better as older API specs.
There IS a specific lifter wear test in the API specs that must be passed... so again, all oil TODAY is as good as or better than old API specs.
The current grade is SN, but yes, they are backwards compatible.
Also of note, the cam/lifter wear test specifies using a 3.8 Buick V6 engines with a flat tappet hydraulic cam.
