Dear Debbie,
 
    Yes, the Cordovan gene can be expressed in any honeybee, including the
Carniolan.  It appears as you described, a copper color.  The color can vary
through selection and some cordovan carniolans appear to be black, but if you
look closely under a microscope you will see they are cordovan.  I doubt you
have a case of isolated breeding.  The cordovan gene has been showing up more
and more lately.  If you purchased your carniolans some where down the line
it most likely came with them, although it may not have been expressed at the
time.  I'm curious as to where you purchased your queens, if you did buy
them.
 
Sincerely,
Joe Latshaw