Does the below info mean the recirculating/dash heater had 3 speed switch and the fresh air heater had a 2 speed switch?
They look identical.
1929-57 Master Parts Catalog
Group number 8.852 PARTS, Hot Water Heater Controls
34-55 Comm., Utility 1st ser SWITCH (high, medium and low w/dash htr) part #3126693
47-55 Comm., Utility 1st ser SWITCH (High-Low use w/Air Flow htr) part #3128267

Has anyone had a 3 speed switch in their hand? part #3126693
You would think the fresh air heater would have the 3 speed switch.

NOS 54 Chevy ALL TRUCKS Recirculating Heater Accessory *PARTIAL UNIT* GM 986896,
Read Description Heater Switch 3126693 (exceptionally nice)
eBay Motors 3126693 3 speed ?

eBay Motors 3128267 2 speed (scroll down)
eBay Motors 3128267 2 speed (scroll down)

1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC