MK3 main engine mount sits in a round carrier, looks like the gearbox mount carrier but bigger so that one isnt.
You might be able to swap between mk2 and mk3 big block gearbox mounts though, but I'm not 100% sure on that one. The MK3 1.4-1.6 lumps share the same box mount as the MK2 so it seems likely, unless the MK3 big block gearbox brackets differ in some way, or maybe the mount isnt quite the same height. Or it could just be the MK3 mounts are beefier!