Tyga would have welcomed Paul McCartney at his performance. Since he was performing after the Grammy's he seems to be unaware of what happened at the door, that Paul McCartney was denied entry twice. In the latest news we read that he has already invited Sir Paul McCartney for his tour.
From what I know of Tyga, he seems to be an individual with a well-rounded view on the world and a good head on his shoulders. In my opinion, he was truthful when he stated he was unaware of the legendary McCartney's appearance and rejection at the door. I cannot think of a single reason why he would not have been anything but welcoming.
I think Tyga would jump at the chance to have Paul McCartney at his performance, if only to save face. Since McCartney's rejection at Tyga's Grammy party, Tyga has been backpedaling claiming he didn't even know McCarney was there, and tweeting comments like "Why would I deny @PaulMcCartney stop it. He's a legend." Tyga's people know he's really stepped in it with this one, even if Tyga doesn't. So yes, I think Tyga would welcome McCartney. The bigger question is, why would Paul want to?
While Paul McCartyney has been contributing to songs with rappers like Kanye West and Jay-Z, Tyga is not a big enough name for him. Paul McCartney needs the best of the best if he is going to perform. Tyga is a terrible rapper so Paul should not debase himself. Paul was on the Beatles, remember.