Uncommon/rare... no... the very fact half the population exhibits this sort of look should make that evident.Local populations can and often do exhibit a unique "look" for a variety of reasons. Is your find cool... oh yes... but nothing that will make you rich or famous.

Unless you're looking at having some nice looking pets and committing years to their care I'd let those two go where you found them... when 5 out of 7 are found dead those two living examples could very well make a difference to the ongoing well being of the local population you've found... far more rewarding ten years down the road imo.

Gerry