Yes, the blanket box is wider and deeper than the standard tool tray but only requires a small amount of modification.
IIRC I modified Dormy's by cutting a couple of parallel slots in the bottom and running them up into the back panel. I then beat this to form a reversed section and closed the gaps with a couple of small aluminium plates. It didn't take a lot of work and I have a Toro overdrive which has an extra top cover and needs a bit more room. The two slots were cut just far enough apart to allow clearance for engine/gearbox movement.
HTH
Dormy