Lovely golden color...great luster...they are very nice!
From experts I've heard that it is very difficult to tell when golden pearls are treated to enhance their "goldiness" (is there a better expression???).
Last year we had a discussion about dyed vs naturally colored pearls (The name of the thread actually shows down below in the "Similar Threads" section, under the name "Edison pearl vs the world) where our own Pattye stated this:

And I totally agree with her.
So, your best bet is to take your pearls to a lab for analysis OR have the seller provide you with a guarantee that the color is natural, which is something you would hardly need if purchasing from a reputable seller.
Wish I could be more helpful...