I know that there are LDS who post here if you know of any Mormons please alert them to this news article so they can rebut if necessary.
I don't believe those "guys" were mormons, but fakes. The major clue is the date that this happened - July 4th - a Major holiday for Mormons who some consider over-the-top patriotic. I checked with my momon friends and was told that the missonaries don't "work" on the 4th - but rather attend congragation functions like the Boy Scout flag raising ceremony/pancake breakfast, picnics, parades, etc. - in other words, it's a "holiday" from their missonary work.