GC 4 Slates

[Rjmoncrief]

Hello All! I know this is an easy question for the mechanics here but do the Slates on a GC 4 always have the wood backing? My understanding was that all the GC Slates have the backing on them. I’ve attached a pic of a sticker on the underside of a GC4 and as u can see it says “unframed”.
What exactly does this “unframed” represent? Educate me!!!

 

[garczar]

Framed has backing board. AFAIK all GC's had frame slate. Pics: https://forums.azbilliards.com/threads/how-would-you-level-this-gold-crown.157136/