Just for starters, it's an M8 not an M20.
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The M20 was the turretless liaison vehicle.
I'm pretty sure we had some in Korea. I seem to remember that Brig Rockingham (Cdr of 25th Cdn Inf Bde) had one and there maybe others assigned as Commanders' chargers.
Since it seems like the infantry is going into an assault on the Shermans, it would make sense that the Brig. was watching to see how the units of his Bde were getting along.
paul