Stage 1 heads

I think I know the answer , but I'll ask anyway. Is there any way to tell the difference between Stage 1 heads and standard 455 heads . I've always read that there isn't

 

Not without removing them to measure the size of the valves.

 

If you have a small bore scope, you can look inside the spark plug hole and see what you can see. I've done that and found which valves it was using.