Steering Head Bearings question

I am needing to replace my steering head bearings as they are bad... my bike is the Twin 650... I am needing after market part numbers on the correct bearings. I have read where people have posted after market part numbers SKF 320/28 X/Q and NAPA BR32 but it is by people who have 800 GS. I am not sure if these part numbers are also correct for the Twin 650. When I look up the BMW parts fische on both bikes for the bearings the part numbers are different... that is why I am wondering if these after market part numbers are not correct part numbers for the Twin 650. I am also looking for part number for the Timken which I hear is the best. Or can someone direct me to a source where I can find the information I am looking for or verify if the above part numbers are also same for the Twin 650. I would greatly appreciate it and thanks so much in advance.