Yeah I have more context in that case, she use haki.
He had black hardening all time? He use it for one time and haki was a case in the middle of pre timeskip.
Luffy should know who has haki or not right?
And not like Zoro, Robin wasn´t able to hurt Monet, someone with haki should be able to do it right?
What has haki do with the technqiue, haki can be use for every technique right?
Because that is a fact, outside of Luffy,Zoro and Sanji no one had haki in the crew.
Do you know more then Luffy? More then Oda and the databook, editors?
If Robin had haki, why Luffy didn´t call her too? Why she didn´t hurt Monet? Couldn´t damage Monet?
Their is no point to debate this with you, it is clear that Robin didn´t have haki during punk hazard and most like DR.