Wormtail and the Mark

[tiggersong]

No: HPFGUIDX 110531

I can't, for the life of me, figure out if Wormtail has taken the 
Mark.  I would think that LV would insist on it, but wouldn't it ... 
well ... give Peter away to the Order?  

Or are they invisible until LV touches his?  I know they darken when 
he's stronger, but I don't know if they're true "tattoos" or if 
they're just magical pagers, so to speak.

What do you guys think?  Does Wormy have the Mark?

Tiggersong