Mine looks like the air flow one shown on pg 36 of the link you sent me.
Yes you have a Harrison Heater
The model number will be on a plate on the back side
Like this Try posting an add in the parts wanted section of the the forum for the rod and bracket.
There is a guy selling rebuilt Ranco valves on eBay for around 120.00us dollars.
If you buy a used valve make sure the tube is intact otherwise it is not rebuild able core.
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