I recently dug out four different 122 BCD Stronglight chainrings for someone who needed one, and found that they varied in several ways. Two of them had "pointy" teeth. (One was actually unused and the other had minimal use, so the sort of "shark tooth" effect you sometimes find on very worn rings wasn't responsible.)

The other two had blunter teeth, similar to what you see on pretty much all modern chainrings.

Sorry, no pictures--they're in my phone, but resist transfer to my computer.

Also, one of the "pointy" rings and one of the non-pointy rings were drilled and tapped for a little screw and a spacer, obviously intended to keep the chain from wedging between the crankarm and the ring.

I've seen these variants before, but never really thought about them. I have a vague notion that the pointed-tooth design is older than the non-pointy one, but have no idea if that's really the case, or when the change from one to the other occurred. I imagine that the same may be true of the anti-chain-jamming screw, but again, no idea. I don't know the provenance of any of these rings, so it's also possible that different 122 BCD cranksets (93, 49d, 63, etc.) were outfitted with slightly different rings, though that doesn't seem especially likely to me.

Since I'm always eager to add to my little stockpile of arcane and useless knowledge, I can only hope that someone here will shed some light on this.