I purchased a used set of ap1 712 from Roger Dunn's. I hit them well and want to order the 4 iron. I notice that all clubs have a serial number and after reading online I found that it must be a nonstandard set if all clubs have a serial number. How do I go about ordering do I need the set specifications or when I order it with the serial number will the ordered club be set up like the rest of the set. The serial number is two numbers followed by three letters. Thank you.