Some of the old purple shaft cams had no identification marks or numbers. I have had a few, the first cam I bought was a used .484 purple stripe cam for $10, because the guy couldn’t get it to idle in his 340. But no identification on it.
I have one of those with the on my stamping on it is on the front nose. “471” is the only thing I can read. I purchased it from my friend. He said it was the 280/.474.