是的，这里的 's mentioned 是现在完成时。

注意：'s 可以是 is / has 的略缩形式，这里的  's mentioned = has mentioned。又如：

He's read the book. = He has read the book.

He's respected by his students.=He is respected by his students.

但是注意，was 不能缩略成 's。如：

He was caught reading my letter. 不能写成：He's caught reading my letter.