Very subjective - and most "professional" appraisers barely understand Shelby's so I would not bet on what they might say.
In general I would agree that a 4 speed will bring more dollars (not saying how much difference) over an automatic.
Often in the sea of cars owners and buyers want their car to stand out so the seek out the unusual features and in your example (likely 67
cars with the lights in the scoops can be slightly more in demand as are, for 65 Shelby's, single or double digit cars. In the case of 69-70's you are allot more likely to find a Drag Pak car if you look at 70's rather than 69's so it depends
At the same time early 67 cars are more likely, depending on your definition of an "early car, more likely a small block GT350 rather than (normally) the higher valued GT500 so the early thing can work against this combination at times depending on the potential buyer
Of course there are no two exactly alike cars so real true comparison is never possible. Leaving us with speculation and guessing
Its all about the demand and less on the rarity Though sometimes they go hand in hand