We have found this is good quality and fit for the money. Genuine seals are VERY expensive and some not available.
This is a full set of rubber seals as shown for your 1973 to 1985 R107 SL convertible. The kit includes all of the seals needed for the soft top, the hard top, the windshield, the rear window, the trunk, the side windows, the doors, and the tail lamps. 107SEALKIT
450SL and 380SL 17-Piece Aftermarket Rubber Seal Replacement Kit
$385.00
SKU:
GEG-107SEALKIT 
Product Details
Here is a summary of the 17 seals included:
1076900797 Post (LH)
1076900897 Post (RH)
1077200178 Door (LH)
1077200278 Door (RH)
1077200578 Hard Top (LH)
1077200678 Hard Top (RH)
1077200978 Soft Top (LH, cut to fit)
1077201078 Soft Top (RH, cut to fit)
1077250566 Soft Top (LH)
1077250666 Soft Top (RH)
1077271130 Window (LH)
1077271230 Window (RH)
1077580098 Trunk
1077580198 Soft Top Cover
1077710098 Soft Top
1077790022 Convertible
1077900198 Hard Top (rear)