if you re at the point where you can run one or not, go with what you like not your wife or the shop guys.
Look at a bunch of images with/without, and long vs short.
If you know yourself, and you don't want any detractors for your own piece of mind, don't run it.
Weather you go short spoiler, or no spoiler you will be in the minority of 69 owners, since most non spoiler cars, jump right up to the long spoiler wether it was an early car or not. Just like cowl hoods, most first gens have them now.
I think the car would stand out more without it, but easy for me to say since both came with my car.
I am looking for another first gen, and plan on running the flat hood, and hopefully no spoilers. (changes the look of the car)