It's 27.8" depth vs 33.3". It'll be tight, and if it does fit it'll limit the recline range of the rear seat. My 50 qt currently has 4.5" of space behind the rear. I could slide it back a hair, straighten the rear seat, and likely squeeze a 63 in. It'll likely make a headache of making any slide option work though.
The ARB fridges have two footprint sizes and two heights.
37: H 16.9” x W 15” x D 27.8”
50: H 20” x W 15” x D 27.8”
63: H 16.9” x W 17.7” x D 33.3”
82: H 20” x W 17.7” x D 33.3”
[Edit the second] Those depth measurements are somewhat flexible too as they're the extreme measurements, meaning the space it would need between two perpendicular walls. When sloped seats and curved hatch doors come into play there's a large fudge factor.