Noob Propane tank question

[kayakterp]

I like the bathroom weigh-in idea that Norty1 uses, I didn't know the empty weight of tank is stamped on the bottoms?
During our PDI our tech told me to never do the "exchange" method because our new trailer has brand new tanks that have been expected without any defects. He went on to say that if we do an exchange, you never know if the other ones have pin-holes. So just get them filled & keep what you start with