Awesome 55 Perla Nera! I want first right of refusal please :puffpipe:
Yes, the Perla Nera stain holds up well over time. It is a special stain process and made from ground up beetles, literally. Thus, it is more robust over time compared to Dunhill Dress Stain. That said, it will fade a bit over time with vigorous cloth wiping. I have two Perla Nera Opera 44 from the 80s and both show a slight bit of natural wood through the stain, both were purchased used and were well loved and smoked. So long story short, the stain does fade, but it's mild, and it's not as bad as with Dunhill.
Below is my Perla Nera Il Gufo, purchased new about 3 years ago. This pipe has been well smoked and polished. Still looks new. That Oom Paul above is from 2016 and I smoke it "all the time" and it's dedicated to aromatics, which tend to burn goopy and hot. It still looks new as you can see.