Another recent pick up is this IWC with cal 8541, from 1968, came on this Gay Freres bracelet, think it's a ref 11, but the clasp doesn't seem to be, but not like any other reference I know. Please chime in if you know more, i.e if the bracelet came originally with watch or not. also the end pieces are not marked, and for some reason don't fit my 666 AD Ingenieur.