will usually tell you which it is.  Other than a few months after CV closed and TER went dark in the US, Kgirls do not typically have their own websites, so the ad link goes to an agency page.  Rates will also tell you.  Indie Asians tend to be in the $4-600 range, while agency girls run $250 to $350 in most venues that have Kgirls.  

 
A confirmation can often be found in the reviews as well.  Many reviewers will refer to her as a Kgirl if she is agency girl. I  do that a lot in my own reviews, not as a stand-alone point, but in reference to something else about her.  I might say "she offers the normal  Kgirl menu,"   or "She is everything I look for in a Kgirl," or she is a little taller than the average Kgirl," or something similar that refers to her as a Kgirl.  

an agency like this are indeed Kgirls.  However, like this site says, they also have some Japanese girls, but its still considered a Kgirl agency.  Most of the girls advertised by Kgirl agencies as Japanese are really a Korean/Japanese mix.   If the ad link only went to a single girl, rather then two or more (this one has eight), then she would most likely be an indie.