As a rule, no. The Generation is an everyday pen from the entry-level range and the successor to the model 320, which it resembles outwardly. Montblanc no longer holds spares for these series. Cracks in the plastic of the section that let ink escape while you write cannot therefore simply be cured with a new part — a workshop would first have to find an identical donor pen and strip it. The cost then far exceeds what the pen is worth.
It makes more economic sense to buy a sound second-hand example and keep the damaged one for parts. If you want to save the pen for personal reasons, the best course is to ask a workshop specialising in writing instruments — Lutz Fiebig (Interpens), for example — whether the section can be replaced.
Do not attempt a repair of your own with superglue: it clouds the plastic and makes it brittle, will not stand up to the stress of the screwed-in barrel in any case, and rules out any proper repair later on.