Quick question: do I actually need to play Postal 1 in order to play Postal 2? :p
I assume the story isn't that important. ;p
I'll tell you what. Gift me a copy and I'll let you know. I haven't played Postal 1 either, so it would be an honest opinion from someone in your exact situation.
(Just to be clear: I'm kidding, don't gift it to me.)