Vwbuge,
You're right, on the 1985 cars they look excatly the same. The thing is that all Mercedes diesels sold in California in 1985 (and a couple of other Western states) has one or the other while the federal cars had neither. It is very rare that the trap has been completely removed, and even then the whole intake setup is usually different than a federal car. If it's an '85 and you see the "can", regardless of which type, it's a California emissions car. By the way, that is NOT true for the later cars where the retrofit catalyst looks quite different from the original oxidyzer.

LRG

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold