As others have stated, your timing chain probably looks better now than when it was new, if you've been changing the oil regularly.
However, the chain rail and guide should be replaced, as a failure of one of these is what typically causes the chain to break. Of course to do this, you have to remove the timing cover. Although there is some labor overlap, it is not much, but you'll get peace of mind in that your timing cover has been resealed and your timing chain rail and tensioner guide will be good for another 150k at least.
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi