Im getting ready to buy seat foam and covers for my buckets.I have a 67 chevelle and Im thinking about going with 67 gto covers.My question is my seats came out of a 68 chevelle The button is on the side and the back cover is plastic.Are 67 and 68 the same?And will 67 covers and foam fit on 68 buckets.I thought the only difference from 67 and 68 was the 67 had metal back covers.Thanks Tom (67 chevelle ss).