Hey Dan,
Production date of 1958 is correct (22nd of July to be exact) for a 1969 vehicle. Here is a photo of the original sticker on the black/red '69 Chevelle. Notice the comparative difference in size of fonts between main body of typing and bottom line in your photo and photo below. Also, note the corners of each (rounded vs. squared). Appears to be more of a paper-ish consistency to the originals.
