You won't find that combo by looking up Shelby taillights though. I think they're 65 Thunderbird lenses (also 68 Shelby) with 64 Thunderbird bezels.
64 Thunderbird don't have the lines in the bezels, 65 Tbird uses a slightly different bezel. Something like that, I forget now.
Yeah they are 65s I have a set in my storage shed I just removed the bird emblem in the middle of them
Image search showed me a 65 as a 64 so I got the years backwards. I know nothing about T-Birds. Doesn't the 69 Mustang valance have more of an outward peak under the bumper than the stock Maverick valance? Something looks different when it's on a Maverick. Maybe a Mustang bumper is wider and hides it.