Based on the color, you actually can. The volume of production could never support it or create it. That said, it is a strand of Tahitian pearls (or at least P. margaritifera), not freshwater. I recommend not spending the money on a lab report. They aren't dyed freshwater, they look exactly like Tahitians, and there really isn't anything else they could be.
PS
Sorry, after re-reading I see there are two strands. They are both Tahitians. I can't see the surface quality in the photos, but the size, color, look ... those are both Tahitians and you did fine.
Lol, Karin, give me a little credit, I spoke up in favor of Tahitians, (I'm just teasing you, of course.)
"To me, the necklaces look more like very well matched Tahitians than dyed freshwater. "
Elena, now you and sis can wear your pearls with peace of mind~
You didn't insist they were Tahitians and tell her to drop the testing, did you? We'll leave that to the big timers, right?
- Karin
PS
Sorry, after re-reading I see there are two strands. They are both Tahitians. I can't see the surface quality in the photos, but the size, color, look ... those are both Tahitians and you did fine.