Native Americans today have access to the same things any other beaded necklace maker would have. The lobster claw clasp makes it unlikely that the necklace is antique or vintage. It doesn't say anything about who made it. However, I'm pretty sure it was not designed as a native american piece because it uses a variety of non-traditional materials. The lapis lazuli pretty well cinched that in my mind. I think you've got something that is modern and was put together by someone who picked the pieces because the colors went well together. I don't think there is a whole lot of deeper meaning.
There can be deep meaning in some of the Native American jewelry. I have one piece that was given to me by a friend, who had a Native American friend of hers bead it specifically for me. She asked her to make it "with lots of protection". I'm not sure what that implies, I'm guessing she would have prayed for my safety as she was making it but I really don't know. That particular necklace is just a single strand with no clasp, with drilled turquoise, and a red stone of some type, plus some silver-colored beads. It's very simple and I've always loved it.
There are also pieces that are created specifically to be sold and you can buy them directly from the artists in little roadside stands on the reservations. That is also what I feel is the best way to get kachina dolls. I have a few of those too. I feel that buying directly from the reservations not only supports the artists, but ensures what you are buying. You should be able to do the same thing online buy going directly to tribal Web sites and dealing directly with the artists.