It is very difficult to replace rear grips and reel seats from the bottom of the rod because the majority of blanks are tapered and get larger as you get closer to the bottom. When you build a rod you slide the components over the tip. If the handle is cork then you would have to ream the cork larger than necessary at the top of the grip and shim it tight. Your other option would be to actually cut the cork grip in half and then glue it around the blank. You will also have to shim the reel seat.
Sharon Johnson
All Star