...I don't have my original kit handy, but the new sheet is likely better than the original. The 1:1 car has some gold leaf lettering; the new sheet duplicates that very well. MPC's attempts at gold leaf lettering often ended up looking like a washed-out murky brown.
I've got to look at the 1:1 car again before doing anything. If it's an XR-7, the original MPC kit will be a better starting point. If not, the Ertl modified '69 kit (altered with considerable input from Tom Carter) will be the better starting point. Either will need a four-speed behind the CJ engine though.
--Mark