74 duster 360 production #s

does anyone on here know the production numbers of 74 dusters with e58 auto?im buying one.....hopfully not paying too much.its been sitting since the late 70s with a short run in the early 90s,51,000 act.mi.bucket seats & console,and according to window sticker it has ....wait for it....4.11 sure grip....that is according to the original owner.i have never heard of this....i will post pix when i get tit home.thanks for any input.
mike bee