DY and GAW: No. Meshaneh Halachos is the proper grammatical way to say R’ Menasheh Klein’s Tshuvos. People say Mishneh Halachos but they’re wrong. Mishneh Halachos means repetition of Halachos. It’s a noun. The verb “Leshanot” means “to change” in modern Hebrew but meant “to learn” or “to teach” or “to repeat” in Mishnaic Hebrew. So “Meshaneh Halachos” is a verb meaning that these Teshuvos are teaching over Halachos.
I don’t know the exact Chelek. I never saw it inside, just a pdf.