There is no such thing as "standard" casino dice. Some are more popular than others, but you can find at least 3 different sizes on craps tables here in Las Vegas.
It sounds like you got one of the pairs of 11/16ths tops (as opposed to the more common 3/4" ones). I can assure you that 11/16ths dice have been used in casinos (both legal and illegal) before.
Jason