They are pearls from the Pinctada margaritafera, so they could be from Tahiti, but they also could be from Fiji, The Cook Islands or even Micronesia. From what appears to be a surface veins, they wouldn't be from Tahiti because the veins are indicative of thin nacre, although they could have floated out of French Polynesia via the back route.
There is some value in them, yes. Not a whole lot though. Either way, it is a nice gift!