Jeff thx and why was this post moved?
It's a general question ??
It may be a "general" for a 69 or 70 owner but not to a 65 or a 86 owner. IMHO its more of a specific question about a certain part and for certain year/application. This is why the site has different sections. It makes finding items, if your a page turner catching up or looking through the site for the first time, to a members specific needs or vehicle quicker or easier. Less heading or searching through other years, models and areas of the car your not interested in at the moment.
It would also be appropriate to place it in the 69-70 Mustang sections and might end up there depending on the discussion, since the rear valance is not model specific (Boss 302) though there are other rear valance styles/types used on some of the 69 and 70's that are different.
so assume the bottom one is 69 only?
No as the pictures show (detail behind the top of the rear license plate) both 69 and 70 has the same design. Your lower example appears to have a flat or straight upper edge (lower one looks like the edge is bent a little - used parts) like earlier (65-68 valances) as well as those lower corner brackets
Example rear valance center shot of two different styles of rear valance but both have the flat/straight upper edge Compared to the later style I showed in my post above of the 69-70s
65 rear valance picture of the end/corner bracket. Looks like its been bent a little inward.
Notice that though the brackets are basically the same you have two different attachment locations
Now comparing