I was a guest and customer at Beaver Coach Sales and Service/Bend Service Center this week. Ty Kelly, the new owner, took me on a tour that included the parts room. He showed me a shelf that has thousands of dollars worth of gauges going back many years that came from the spares where your motorhome was built. He also told me that his shop staff has a collective experience total of about 250+ years of working at building or fixing Beaver motorhomes.
If you can't find your answer here on the forum, calling them will probably provide it.