A trivial internet search busts your claim to priority
1999 discussion post, referring to even earlier use of the phrase.
It is common to pick up on other people's phrases and claim them as your own. Often unknowingly as to the source. I found myself the other day quoting Scarlet O'Hara's last line from "Gone with the wind" "Tomorrow is another day - I had thought it was Hemmingway.
"Vietnam with sand" was used quite a lot in 2002, so you probably picked up on it subconsciously then.
We all get confused, some more than others. A humble attitude helps avoid friction...