I HAV BEEN GIVEN A COLLECTION OF BROWNIE DOWNING, SOME PIECES ARE SIGNED ON BACK WITH THE WORDS REGISTERED DESIGN AND SOME ARE BLANK BUT THEY ARE IDENTICAL TO SOME OF THE WELL-KNOWN PIECES. MY QUESTION IS ARE ALL BROWNIE DOWNING PIECES SIGNED OR ARE THERE COPIES. HOW DO I FIND OUT IF THEY ARE GENUINE. THANKS