Crossword Puzzle '-- it?' (knock reply)

Clue: '-- it?' (knock reply)

It equals 0.3937 inch (CENTIMETER with 10 letters)
Super Bowl to be played in the year 3968, at the current rate (MMII with 4 letters)
Knocker's reply (ITSME with 5 letters)
39th of 50 (NORTHDAKOTA with 11 letters)
Alma mater of the 39th Pres. (USNA with 4 letters)
39th VP (AGNEW with 5 letters)
Do a scathing impersonation of the 39th president? (MINCECARTER with 11 letters)
Knockoff merchandise items? (METOOPRODUCTS with 13 letters)
39th vice president (AGNEW with 5 letters)
39th Veep (AGNEW with 5 letters)