Spare Rim

not 100% sure on this, but I have also noticed it on other "stock" a-bodies... the spare was I believe to be a 41/2 rim to save space... if you notice when you mount a tire and 5.5 spare in the wheel well for spare, then the wing nut, mason board, and trunk mat all become disoriented with the 5.5, and the 4.5 it all fits nice and tidy...