I don't presume to tell you what to do, but decades-old decals can be difficult to use. As they age, the adhesive can go bad, and damage can occur during storage. And some are priced rather steeply due to the perception that NOS is better than reproduction. I think that NOS stripe kits are one of the parts that could be worth much less than a quality reproduction. If this is the route you choose, then my advice is to proceed with caution.
There are brand-new stripe kits available that are cut from freshly -made vinyl and are easily applied. The reflective '68 stripes are unique, though, so maybe they are not available in the color you seek? I know that there is only one supplier of BOSS 302 stripe kits that uses vinyl that reflects in the proper gold color. I can't tell from the wording of your ad whether you are asking for a gold-colored kit, or one that reflects in gold? Good luck with your search!