Well, while I agree w/Larry that both 103 and 104 have a great chain histoy and set-up, If I were already in there and the engine was pushing 200K,the short $50 for a new chain would certainly be on my list.
But, at the same token, I also would not go and tear one down just to satisfy the common Benz chain paranoia..
It's a judgement call and if you see any other wear items that indicate poor maint./oil changes, you may want to consider it .. all parts wear out.
PS.
Do heed Larrys tensioner tip.. these units ratchet and lock in length as the chain wears to keep the tension from releasing when there is no oil pressure
[ engine at rest]. This is one of the reasons for lower chain failure on these type systems. So, the tensioner has to be reset when doin any work , such as head or chain change.
There are post here in the archieves where this was not done and camshafts were broken due to to tight of chain tension. A simple, costly oversight...