I posted about my grandad's Parker pen before Christmas and got some great answers on this forum! So when I was able to buy a worn and somewhat damaged Montblanc 342 for a pittance from a friend I jumped at the chance. I have some questions about it though, that I thought that you experts here might be able to help me with.

First, here are some pictures:
Album on Google Photos

I have a number of questions about this particular pen that I hope you can answer!

First of all, the nib says Monte Rosa, which I've learned from googling, is a completely different pen from the 342 that the cap band inscription says it is. The rest of the body has no markings whatsoever. I am not skilled enough to see any differences between a Monte Rosa body and 342 body from the shape. How can I tell whether someone has fitted a Monte Rosa nib on a 342 body, or if it's the wrong cap on the pen? The cap screws on perfectly btw.

The 342 cap has what looks like a small drilled hole about half-way up. Is this supposed to be there?

The nib is damaged. It has a small indentation on the left hand side (when holding the pen with the nib upwards and the front towards you). I don't think this is more than cosmetic damage. The tines are bent as well, slightly to the left as if pressed too hard when writing. Is this fixable, or should I get looking for a new (but still old) nib? The pump mechanism works beautifully, but using the pen feels more like scratching the paper with a needle than a nice writing experience.

Finally, is there any way to date this pen other than "the 1950s"?

And to be clear, I didn't scam my friend or anything. He is fully aware of what a Montblanc pen is!