Gentlemen, thank you for replies!
On the color: again, if you look at the Technical Manual, Upholstery codes section, bottom of it - you will see images of building instructions for 280SL by upholstery code. If you look at code 245, you will see rubber linings in blue. Alfred has recently posted a list of alterations to this schedule when he was helping me on center tray material. I but I do not see, however, any point on the colour of the entry area lining. So I am aiming at blue.
Asking upholstery specialist can definitely be a way of doing this (Brad, can you share their site address?), but wanted to check if, perhaps, anybody supplies that done in blue. SLS don't, Niemoeller don't, couple of others in Europe don't, I am not even writing about Mercedes - not worth it, so I thought maybe in the US there is someone.
I have recently found on e-bay blue linings, but the seller had them only for 107.
Thanks for help!