Silent block installation issue

Good Afternoon, 

I have to install my new 912is and i discovered that outside diameter of rubber silent block ( the short straight parts before slope side begin) is less than internal diameter of steel silent block housing ( on engine support).

Ther's 2 mm of gap all around of silent block .

The recessed part fits perfectly .

So i don' t know if is ok like that or i have to reduce the internal diameter of silent block housing welding a thin 4130  ring

Grazie

MArco