[Janezki]

It will shift to third in both cases, just that the transmission will lock itself if the clutch at second gear is solid. With normally operating 2nd gear clutch it will work just right.
Getting the truck to move from standstill without 1st gear is problematic - you have to adjust the clutch at 2nd so that it will engage right when you give throttle. Otherwise the motor spools up revs until the clutch engages and then your truck launches with a bang (or brakes gears...).