OK - The Target issue is resolved - I shot off an email to Steve, and here is his reply ;
"White Hot Stamped(And they are hot stamped) need to be covered with protective Mylar.
Since the 1980's, the formulation of the stamping foil has been changed to remove the lead(By Law), resulting in less durable white stamping "
So I'm going to have at least the "6" replaced, and I will mylar the others tonight.
Steve has offered to replace whatever targets I deem to be damaged. I believe that there are only one or two.
I will be mylaring all my targets, or at least asking if they are using the new technique to stamp them.
That's a handy thing to know for future reference.