K3 and K1 uses the same I-129F form. First I filed K1 and then I filed K3 after filing I130. So now I am withdrawing K1, when I did send two withdrawl letters of samething (K1) to two addresses caused K1 withdrawl first which is correct and then they withdraw the K3 too. Which is not correct. It is their fault.. but what can I do. In your case, it should be OK, go ahead and file K3, it does not cost anything. I see in some cases it helps to speed up I130 approval. It is not guarantee to help it did for some case. but it does not hurt. Good luck