Best thing to do is contact either Licensee or WMS direct. They probably won't provide you with a list of licenses they own.

The other thing you can do is engage a professional in copyright laws.

Either way, there will be plenty of red tape and costs involved.

The licensees paid for the right to own these licenses, and they will actively protect their assets. At the end of the day, you risk being prosecuted by either licensee, WMS or the third party licensee.

So if you were to illegally reproduce Addams Family Decals. Be prepared to hear from ;

WMS
Either or both licensee
Paramount Pictures
The Addams Family trust
and others..

Hypothetically - if you owned the equipment to produce sideart - You could contact either licensee and ask permission to reproduce the decals. Send a sample to either licensee, which would be forwarded to WMS. WMS would contact Paramount Pictures, Addams Family trust and other rights holders. If ALL these parties agreed - You could write a contract with the licensee and produce the decals. Then you would be under license to produce "with permission".

Now if you did do this (with permission) and some other dude prints out decals out the back of his shop with a cheap inkjet and sells them off as "originals" - You would be pissed ?