The consensus is to change the oil tubes. I think they were redesigned. They are also cheap.
You can do a search on timing chain, and the standard advice is to change the timing chain, tensioner, and upper guide rails every 100,000-120,000 miles. There are those that say you can go longer, especially if you've done frequent oil changes, but if it were my car, I wouldn't let it go longer than 100,000 miles. You know, for piece of mine. That's why it's called preventative maintenance, don't they?
I haven't done a timing chain replacement, but have read several postings from those who have done it, and can't say anyone has ever done it this way.
Again, I recommend trying the search function for 'timing chain'. There are tons of posts in the archives.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".