Allis WC engine

I recently bought a 1937 allis wc, it has the distillate carb and auxiliary gas tank, so I wanted to check the engine number to see if it was truly a distillate engine, and it started with a "W" like it should, but instead of ending with a "K" or "G" like the book says, it ends with a "HA" and I read on a different forum that it means it was tuned for High-Altitude, and I just wanted to check if this was true, and if there was still a way of proving its a factory distillate engine. Any knowledge on it would be greatly appreciated, Thank you.

I was seeing that myself, any ideas on the best way to do that? I've seen and been told not to trust a compression test of hand cranking, my thought was hook the belt pully up to another tractor.