Gotta love those Chevelles. I owned a 69 396/375 when I was 17 back in 1972. 13.40's @ 102 MPH, running headers, and a set up 780 Holley, with L60 Goodyear Polyglass. Should've never sold it. Funny thing was, it wouldn't be a "matching numbers" car today. I bought it from the first owner who had just had the short block replaced under warranty at around 30k. I was glad I had a fresh lower end, but a purist would say it wasn't original. My car was a Michigan car and had a little rust starting to show on one of the lower front fenders even back then. That same fender had a crease in the eyebrow above the head light so I replaced it. If I remember correctly it was around $150.00.
GM now has a huge licensed reproduction business. Many parts are made, including sheet metal, using the original tooling. These parts have to meet GM standards as for the original parts. Look for GM licensing and make sure your supplier is in fact an authorized reproduction maufacturer. Your parts dealer should be able to tell you. If it's real it'll fit like it was originally supposed to. Good luck with the prettiest Chevelle, Chevy ever built, the 1969.