There is a Dick Menchaca who had some professional fights out of Texas in the mid to late 40's.
http://boxrec.com/list_bouts.php?hum...6278&cat=boxer
More info here:
http://boxrec.com/media/index.php?title=Human:206278
This looks like an amateur flyer/broadside. If it's the same Dick Menchaca, which it looks like it's a pretty good chance, I would guess it probably dates to before his service in the military, c. late 1930's to 1940 or so.
Not really much value. It's the type of item I might park on a website for 15 or 20 bucks and hope a relative stumbles across it eventually.