I would assume there is truth to the story that the NFL has this concern.
As to whether there's any truth of deer antlers delivering to the bloodstream any remotely significant amount of IGF-1 when applied by spray, I would really think not. Proteins are just not at all readily delivered transdermally. That's why we don't spray on insulin or GH.
EDIT: Apparently it is an oral spray.
Still, I don't think it's credible and I don't think it's demonstrated that IGF-1 has significant oral bioavailability.
If there's any effect at all, it's slight and not remotely comparable to doping.
Maybe the NFL should ban steak. Meats have IGF-1 in them too. And testosterone.