Might be even more than 3mm. Many cases that's the clearance for the steel panel or the steel and silencing foam, they use the same measurement to cover TG too, even though there's a bigger gap. A solves them of risk when you close the panel and scratch the glass.
I suppose the 3 mm clearance is safe enough. I would do it.
With one case I had less space / less than 1 mm. I put some (thermally resistant) very thin silicone, just to avoid accidental scratching and made the side panel to be very slightly curved in that area (it was a steel side panel !!)