It's very likely they looked at the wrong place.
Let's recall the Motown quads history:
2 titles released in USA as Q8 (Diana Ross live, Marvin Gaye live)
16 titles released as CD4 in Japan
The only shared release is Diana Ross live.
IMHO, since the big differencies that are present on the Japanese CD4 studio albums compared to the regular stereo-mono releases, it's very likely the Motowns has been mixed for quad *in Japan*. Motown USA didn't had a interest into quad and the only two releases were poorly distribuited (Jon, you can chime in...), so at the Japanese request for quads they shipped out a bunch of multitracks without ever checking if these were the right takes. Regarding "last time i saw him" probably it was a copy sent out from Japan, where it has been mixed and released on cd4, for a possible release as a Q8 in the USA that never happened due to poor sales of the two "test release" of DR and MG.
If i was in charge of the thing i will dig out the Japanese vaults, not the USA vaults
Is there any way of getting some Quad/surround effect out of the "Last Time I Saw Him" Quad mix that's in stereo on the Hip-O Deluxe Edition 2-CD set of the album?
It "does things" via PLII but I think they're just random out of phase things rather than any semblance of Quad decoding?