If you are running a solid roller you can groove the cam. If it's not you don't need the groove. FWIW unless the shaft is coated I mirror polish them all. I have the same rockers and shafts you do, and mine don't look like that.
I run no less than 50 pounds of oil pressure at hot idle. Especially if it's a plain or bushed rocker. Needles can use a bit less but there are other reasons not to run oil pressure low.
