I've got an old 12 bore Westley Richards BP percussion double and the stock has a cheekpiece.

I thought this odd, and wondered for a minute if it was a case of "mix 'n match" somewhere down the line, but of course, the stock is original to the total gun,as odd as it does seem.

As an aside, when did such a stock w/cheekpiece pick up the label "Monte Carlo" stock, and why?