The tapes would be hi-fi, but the films themselves would still be mono, because that’s how they were mixed. (No Godzilla film had an English dub in stereo until Godzilla vs. Mechagodzilla II. In fact, I’m not sure if any Japanese film ever had an English dub mixed in stereo, U.S. or “international”, until the Streamline dub of Akira!)
But yes, a PCM capture would be perfect, I would think.