I get e mails like that occasionally, but never have seen an old fashioned paper letter of that sort. That letter would make a decent fire starter.
The very first one I ever saw was a letter mailed from Nigeria.
At the time I had a really fast 14.4K modem, so that tells you about how long ago it was.
Today the emails don't make it past the spam filters, so it's back to snail mail to get round them.