Postcard from Niagara Falls

Regular commenter Sara went to O! Canada! (and many other places) on her recent vacation. She sent me this postage-paid postcard, telling me of her great surprise and delight at Niagara Falls.  It’s dated July 1 and just arrived today on the 28th.  I can’t decide if it’s an international thing, or perhaps the wrong zip code.  The last two digits written are crossed off in inky black and re-written.  Perhaps some postal employees went the extra mile to make sure I got this?