Hi John,  Please take your 7 iron and serial number to your local pro shop and have them set up the repair/replacement for your club.  It will depend on what model AP2 you have as to whether they can replace it. 

Shafts generally come 46-47 inches and are cut to length.  After standadard tipping, the length is adjusted for length from the butt end.  This won't impact the shaft's response.  Getting a 45.75 driver instead of 45 will primarily affect the swing…