Hey all, the dial on this Deville looks legit. Anybody have any idea of what the blue on the back is?

 

It looks like "purple snot" (the name for the protective laquer used by watch factories).

Usually applied to the back of brand new watches in times past to prevent scratches, nowdays the back is usually protected by plastic film.

This could have been there since new if the watch was rarely worn or even "NOS".

EDIT

Could even be that somebody added some clear blue laquer to the background to make the medallion look nicer, similar to the Longines vintage casebacks.

 

Is it removable? Or would it be more prudent to leave it on if one were to purchase it?

 

I'd leave it if it was me, it could always be removed at a later date if you had to.

 

Just purchased it for $600 AU. Thanks for the Info, mate! I've always wanted a Deville!

 

You do know you will be banned from ΩForums if you don't post some good pics when you get it.

Don't you!

<that's a joke, love to see some good pics>