Just to update. I've determined that I have to replace four additional grommets and have so ordered them.
For informational purposes, I am listing the part numbers of the rubber pieces that can deteriorate and should be replaced for a water tight firewall. The picture and part numbers have been taken off my 1983 300D.
A) 123 997 32 81 Main Electrical Right grommet
B) 123 997 12 81 A/C Refrigerant Line grommet
C) 123 832 36 94 Cowl Drain Tubes
D) 007 997 58 81 or 110 997 14 81 Speedometer Cable grommet
E) 123 997 11 81 Oil pressure Gauge line and vacuum line grommet
F-1) 123 301 04 97 Accelerator Pedal linkage boot
F-2) 123 462 13 96 Steering shaft boot with power steering
G) 123 997 07 81 main electrical cable left grommet - (below the fuse box)
H) 123 880 01 59 Hood release cable assembly - grommet is not sold separately.
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