Great design 
Unless I missed something in here, you never did actually confirm what the “leather” layer is. They list it as “PU” which is less than helpful. Someone in the reviews seems certain it’s petroleum based. The thing with PVC is it can engrave just fine - but the invisible particles start eating your machine and there’s no way to stop it except literally hand cleaning every bit.
So please be very careful engraving unknown things.
With the number of reviewers talking about engraving them you’re likely safe - but you need to know you’re making a decision when you engrave something like that.