Is 7 Groove Case M3 unique

I have added to my collection a WWII blade marked "Case M3" with a 7 groove grip. Cole's example shows knife with 8 grooves and I've seen several listings online referring to a sellers "rare 7 groove Case M3". So my question: Is the 7 groove rare and somewhat unique? Or is it just a variation that adds no more value to the knife?
Thanks.

I've seen examples with 7, 8...don't believe just because the sellers say they're rare means it's so. Look on line and see, count how many you find with both...