Appreciate the tips.
Enquired with my local MB dealer who said the seals are not available separately, I need to replace the rear glass at over $340
Enquired with Phil and it seems the seals are available separately from the glass at a much more reasonable $32 ea. So I ordered both sides.
Left Lateral Window Seal SPECIAL ORDER 1246700939
Right Lateral Window Seal SPECIAL ORDER 1246701039
Installation will be interesting.