Hi
Pity you don't live in London UK! there's a guy near Manchester who replaces all the windows in a 107 hood for £270 - fitted - propbably not mmuch more fopr a 129! But you might find it cheaper to replace the whole hood - there must be places in North America who do them - in the UK we've people like the following:
http://www.prestigeautotrim.com/uk/hoods/mercedes_hoods.htm
I suppose shipping isn't too much.
Cheers
Jim