I have several upper radiator hoses NOS (New, Old Stock) for the 300SEL 6.3 and 600 models.
Part number is 100 203 06 82 (Old # 100 203 04 82) $30 each. These are the bottom hose in the photo.
Located in Poway, CA Still available as of 8/5/25
The lower hoses have all been sold.