Um...I found no difference between Studio Periot 
production cels and it's reproduction cels.

I got the production cels of clamp camplus and 
the reproduction cels of Hikaru no Go....the only 
difference I can found is, the production cels 
got sequence number while reproduction cels 
doesn't...

Their reproduction is really good in quality, and 
Studio Periot always chose the right scene for 
the reproduction cels! Hope this information can 
be a little bit helping ^^6