I just received my 712U 3 iron and noticed that the shaft label says it's an X100. However, I ordered a hard stepped Dynamic Gold S300 and the receipt in the box reads "S300 Hard stepped once." I spoke to a Titleist customer service rep who said that it is likely that the wrong shaft label was put on the club and that I would have to cut the grip off to read the serial number to determine what shaft is actually installed. 

After doing some research, it seems that I may be able to determine what shaft is installed based on the height of the first step from the tip. If so, what would I need to measure to determine that the shaft is indeed a hardstepped 3 iron? I don't want to cut the grip if possible. Thanks.