Cboy, I have never used one of those kits, but I worked at a glass shop for four years. We used the really nice metal injector kits that worked good on most chips.
If you decided to try it you need to clean the center hole of the chip carefully with a pick so the fluid can get down into the crack.
When you inject the fluid do it slowly and you should see it fill the crack, if you do with to much pressure you will run the crack further out. Fun to watch but will ruin your day!
Good luck if you try it, let me know how it works.
Decided to go the safe route and had a pro do the injection. If it had been on one of the family cars I might have tried it myself but didn't want to do something stupid and cobble up the '32. The guy did a nice job, BTW. There is still a very slight mark where the original stone hit (and glass was chipped away and lost) but the crack itself is no longer visible at all. I was pretty happy with the outcome. I know it is there but 99% of the people looking at the truck will never see a thing.