He might be right, he might not. That's the great thing about the people the president surrounds himself with, they're liars. Even if they are telling the truth, how would we know?
However, the reports coming out seem to indicate that Cohen is fingering the president in relation to some Russia deal. The president says he is lying, BUT stated that their would be nothing wrong if he did. That, at least to me, makes it seem Cohen may be telling the truth, since the president did interject that caveat.
Mueller may have the answer.
Fingering the president for a deal that was in the works before he became president that never came to fruition? Trump has acknowledged that. I don't see how that implicates Trump at all. The only one that he (Cohen) seems to be fingering is himself for lying to Congress.