Are the R107 "subframes" under a lifetime warranty?

[luvmy84300sd]

Hey Everyone,
My 77 450 SL (german model) has a few holes in the floorpan. I ran into someone several months ago who said his was a little more than 1/2 rusted out and Mercedes replaced it under a supposed lifetime warranty. Has anyone ever heard of that?? I called the vintage benz line found on MercedesBenz.com and the guy was a little evasive and said I must have it checked out by a certified MB service center. When I asked what they could even offer, he replied he wasn't able to say over the phone. I called my local dealer and the service advisor has never heard of such and any repairs would be my responsibility (monetarily, that is).

Thanks for any feedback.