I have euro's on my 85 500SEL.
They were installed by the PO, so am not sure of any modifications, or direct fasten method was used.
Being it is Father's Day Weekend, I am fortunate to have the bosses (my wife) approval for a 3-day golf weekend.
I will take a gander when I get back on Monday, if you still need help.
Be patient, the euro headlights are worth it !!!!!!!