I'm doing almost exactly what you are except I have a 69. I too wanted the 69 sport fury covers but no dice. Then I got a hold of 68 buckets and saw those exact 68 300/Newport covers and ordered them as well as 68 bucket foam. Got the 68 rear covers too and...
.they dont fit my 69. Too narrow. 68 Armrests were wider and the seat is therefore shorter. Top and bottom. probably 5-6 inches on the bottom and 4" shorter on the top. I'm looking for someone to sew new ones and use the inserts or whatever they can. I'm a little nauseous. In my defense I was allot younger and more stupid when I initially put in the order!
I don't know how the 68 bucket covers would work on a 69 frame.
I suppose I could use this as an excuse to use 68 rear seats making room for tubbing the wheel wells
Oh, right when I called legendary about confirming the width difference and inquiring about similar 68 style for 69 they had no info. Just what's in the catalogue. Seemed strange pulling an Autozone on me. . Maybe I caught them on a bad day. I think they said orders placed today are coming in FEB.