Jason, save yourself some money and the hassle of finding the stock grip by using a bike end bar (made from aluminum). Not only is it going to probably be much cheaper than what Minelab charges for parts (well south of $10 at a bike shop), but it's also going to be MUCH more comfortable than the stock grip. The stock shaft I only use for my water rig because I built a light weight land shaft, but even on the stock shaft (water rig) where I used all the stock parts, I ditched the stock hand grip for a bike end bar on that as well. The stock grip never felt "right" to me. Didn't like it's angle, and it just didn't feel comfortable to me. A bike end bar is MUCH more comfortable, and in fact you can pick any rubber hand grip from a wide selection at a bike shop that strikes your fancy for looks and comfort to put over it. Many of these grips are gel packed and make it much more comfortable on the hand after a long hunt. Not only that, but I also didn't care for the foam on the stock grip. In the water it would stay wet and I didn't care for that alone.
Usually bike end bars come in a two pack. One end bar will curve one way and the other will curve the other for the left/right sides of the handlebars on a bike. I use the end bike that has it's curve slightly to the left, as it seems to make for a comfortable slight angle when hunting right handed as normal. If you are left handed them probably use the other one. Now, don't let the curve in those end bars scare you off. If you notice most of the curve is near the top, and you don't need all that extra length anyway, so I took a hack saw and cut off the unneeded upper length of it. I left just a bit of it right where it peaks and starts to "hang" over your hand, as I then mounted a trigger switch inside the end bar with it's trigger hanging down from it so just like a Whites I've got a trigger switch to go into PP mode on my GT. Oddly, though, I never use PP hardly anymore to PP a target but prefer discrimination to do that.
Anyway, some end bars are more curved than others, so find one that you feel is the best. Some of the rubber grip covers even come with those snap on end caps to hide the hole in the end of the end bar, so I used one to seal the end to keep water away from getting to the internal switch I installed. I put some shoe goo on the end cap before putting it on for a water right seal on my land rig as well as my water rig.
Just want to say, these end bars with a good rubber grip on them are TEN TIMES more comfortable than the stock grip. I actually even think they are lighter than the stock grip as long as you don't put a real heavy rubber grip cover over it. That was important to me in building my light weight land shaft.
One more tid bit...When I bought my GT used I noticed the prior owner had the stock grip on BACKWARDS. In other words, with the slight tilt in the grip going TOWARDS the user and not AWAY from the user like it should. For that reason, even if you guys are using the stock grip, make sure it's pointing the right way for best comfort!