Many years ago. Foam is easier than cork, but not as desirable. Cork comes in smaller 'disks' that, when done, need to be sanded to shape & smoothness. Both need to know the diameter of the rod's shaft so you can push on and glue. That's about all I can remember. (At the time, 51 years ago, I owned my own sports shop and had wholesale catalogs to choose what I needed at cheap prices.)
Thanks..it's EV foam grip material and it's at Jann's Netcraft not Capt. Harry's. They have upper and lower pieces and a few to choose from. Inexpensive so I'll order some. Looks like they use 2 part epoxy to put them on.