Yes that symbol means pounds in the USA. However that still dont say much about propane capacity in tanks. With it being a MH it "might" actually tell the capacity in gallons. Most newer MHs do, alot of older ones do not though. Horizontal filled tanks get filled by volume. There is a bleeder valve near the top. When filling, that valve is opened, when liquid escapes the valve opening, the tank is full (well 80%-that is the limit to which "any" propane cylinder can be filled)
As far as portable cylinders are concerned. There are codes on the neck that is to be used when filling. There is a formula that uses those codes, that determine the "weight" the cylinder will be when full. Therefore they are filled by weight.
Tim-DW(Kathy)
12 Chevy Sonic DD, 03 JEEP GRAND CHEROKEE, 2001 Jayco KIWI
If a "nightmare" is considered a dream-then I am living the dream