I found the same listings as Eric, and these cars are present in my 1930 ORER, but not my 1935.

I think they are "legitimate" class HT cars.  There is a clamshell-type hopper chute just in front of the KD air reservoir, and probably a second one hiding behind it.  The design is somewhat reminiscent of the D&H's Seley hoppers in their as-built configuration, absent the steel truss.
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Dave Parker
Swall Meadows, CA