If the nib has the right size, they are interchangeable.
I have screwed a vintage 140s nib into a M150 and vice versa (140 was broken but I wanted to use the nib ....).
And I have swapped nibs between vintage 400s/400NN and M400s. Everything works fine.
If the nib screws in (I have a 400 with a friction fit nib!) you simply have to find the correct size. Check "New pens"/"Pelikan" on
richardspens.