I LOOKED IN THE NCRS BOOK AND IT SAYS THE WORD SCHRADER SHOULD BE ON THEM. I HAVE AN ORIGINAL SET AND IT DOES NOT SAY IT, AND IT DOES NOT HAVE A HOLE INDENTED IN IT. SOMEONE TOLD ME THAT 1968 TO 1969 HAS THE HOLE IN THE CENTER OF THEM,AND 1970 TO 1973 DOES NOT. CAN SOMEONE PLEASE STRAIGHTEN THIS PROBLEM OUT?