As I understand it, yes. This popped up on another site somewhere and I checked it out. "SL" rated oils have high levels of zinc like needed for flat tappet cams, "SM" rated oils do not have high levels of zinc. Check you bottle of VR1, I think you will find that its rated "SM". Mine are.
This is off the net about the API ratings for zinc in oil (its in the little circle on the label on the back of the bottle):
"SM-grade oil will have less than 600PPM (parts per million)of zinc, while SL-grade oil will have about 1100PPM of zinc. Higher viscosity SL oils (10W40, 15W40, 20W50) have a higher level of zinc at about 1200-1300PPM."
