oil

Should the notch be there, or is it supposed to be completely round? It's off of a 2010 dragon 800 iq, part # 2520901, we believe.

Good evening all, I was wondering if anyone on here has run any other oils other than the polaris brand like Amsoil in a 1999 xc700 or an 01 500 classic. I'm just curious on everyones pros and cons on amsoil.