I’m speaking specifically about Jim Dunlop picks, but this question could be for any manufacturer selling signature picks.
Is there a difference besides color and graphics between a signature pick and the standard version? In other words:
Does a John Petrucci Jazz III differ in shape/material etc. than a normal Jazz III? Is the Animals As Leaders Primetone different in some significant way from the standard?
Etc.
The Petrucci Jazz III is quite different from a standard Jazz III, but his primetone Jazz IIIs are basically Ultex Jazz IIIs with his preferred edge bevel worn in. The Trinity pick is something new entirely.
The Eric Johnson Jazz III is just very slightly larger than a standard red Jazz III, but it’s made of a matte nylon which wears smoother.
The Kirk Hammett Jazz IIIs are very similar to the standards, but with a notch cut into the round side of the pick. Supposedly, the notch is for grip.
Thanks, Tom.
“Signature” anything kind of drives me a bit nutty. A custom bevel or specific non-standard size/thickness…OK.
But the Kirk Hammett pick? Ugh… The notch is for grip?!? Okaaayy…
Back in the day Reb Beach had the body of his guitar carved out behind the bridge to resemble a Steinberger GM/GR.
…at least he was straight up with his reasoning. 
I really don’t have any problem with signature models, especially not when it they offer some unique feature not available on a standard models.
For whatever it’s worth, I have a small pick pouch on my keyring. I have three picks which I carry with my everywhere. Two of them are signature picks (EJ Jazz III and JP Trinity).
I guess I’m just ranting a bit. 