I got my first P51 today and I just find out that is Mark III. I just read that this pens were not made with the same materials as the Mark I or Mark II; instead of lucite the used a softer plastic that is more propense to shrink and scratching. My pen is in excellent condition, actually I think Im the first owner, so my question is: how much time does my pen have before any signs of shrinking or finger wear marks or anything like that? I'm kind of sad because I bought this pen for its bulletproofness...