That diagram is for the 103 engine, which the 190E 2.6 has, so yes it is the same for both the 2.6 and the 3.0 (300E).
The 2.3 was an inline 4, so I'd imagine it would apply to your 190 as well.
The CD states to put sealant on both sides of the bracket hole. When I replaced my tensioner last week, I had oil caked along the bracket rail facing downward. I sealed it back up and no more leaking.
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi