Boy that link spells out just about everything about wheels.

JK 14" x 7" Rally II 4.75" bolt center 4.50" backspace 2" center bore

IF 14" x 7" stock steel 4.75" bolt center 4.50" backspace 2.75" center bore

A note about the IF code wheels. These are the wheels that came with my conv when purchased. I don't know if they are correct code for '69 but they are the correct dimensions. JK code Rally II are correct for '69 Firebird, GTO and GP.