If you want to see if either or both grip panels seats correctly on the that pin,,or if the hole in either panel is off,,remove the overly long pin from the mix first and try the panels separately.
Do this by removing the grips.
Then punch the pin into the grip frame deeper on one side but not completely flush with the frame. You are just driving it in a little to mimic it being shorter on that side.
Try the panel on that side (only) and see if the panel fits OK or not.
Remove that panel.
Flip the frame over and now drive the grip pin (which is sitting way too high out of the frame) down to a level where it would sit if it was the correct length on this side.
Again try the grip panel for this side of the frame and see if the grip fits OK on the pin and up against the frame.
If everything checks out OK,,then just shorten the grip pin.
>Use a punch and knock the pin out of the frame.
Put the pin in a vise and file the dome portion off of one end.
Then with the pin still in the vise, file a slight chamfer on the edge of the now flat headed pin.
No file the pin down flat to remove that chamfer.
The idea of the chamfer is that you can see the amt you are removing from the length of the pin. It's the amt that the chamfer cut is in height on the end.
No I don't necessarily measure it,But I'd have a good idea about how much to take off from trying the grips on and they didn't seat to begin with. One of those 'about that much' measurements.
After the pin shortening,,leave the pin in the vise and now file the end to the shallow dome shape of the original pin. This is to allow the pin to guide itself into the hole in the wooden grip w/o scrapping the edge of the hole and enlarging it.
Polish the end with a bit of 320 or whatever you have. Cold blue it if you have it or heat blue it over a torch flame or Ma's kitchen range burner.
Lightly oil it and replace it in the frame.
Try the grips again gently. They'll most likely seat just fine now that the pin is shortened.
If the grips didn't fit in the first place when checking in step one because the hole in the panel(s) was off, then you have to enlarge the hole(s) in the panel(s) to get them to slip over the grips.
Once you shorten the grip pin, then you bed the grips solidly with a tiny amt of epoxy bedding mtrl in those oversized grip pin holes.
You can use Stock Bedding Compound like the stuff from Brownells or just something like JB Weld which works great for small jobs like this.
I use soft auto wax as a release agent on the metal applied with an old tooth brush. Apply enough and let it dry,,don't buff it off just let it dry on the metal. Put a small amt of the epoxy in each oversized panel hole and replace the grips. Screw them on tight and let them sit for 8 or 10 hrs.
They may resist coming free at first, but careful tapping on the unscrewed grip screw and a very thin knife blade betw the wood and metal will pop them free. Clean up any excess epoxy inside, clean off the 'wax',,oil things up, put the grips back on and head to the BB-Q.
Well that's what I do anyway.,,maybe not the BB-Q part but fixing the grips and pin thing.