GGR
The air conditioning was always installed by the dealer, but the 70 and 71 cars were already fitted with that aluminum insulation material on the floor boards (which weren't actually made of board :-)... The 108 springs are correct for your car. I think Mercedes anticipated a large amount of these cars would be fitted with dealer installed (factory authorized) AC systems and if you look at the spring charts in the BBB you'll find that the stiffer springs were separated by groups of additional weight, like automatic transmission, hard top, AC, etc...., so it didn't matter too much if the car ended up without the AC.
You wouldn't believe how many differences I've seen in the way the dealers followed the MB/ Frigiking instructions for installation. Some (not few...) even went so far as to hack saw (torch cut) out the baffle plate for the air cleaner housing to make more room for the AC compressor installation and servicing. All in all, these AC systems were quite a nuisance and detriment to the life of various components inside the Pagoda although they could be made to work satisfactorily if you take your time. You certainly won't lose any value by removing it and keeping the parts for the next owner and Alfred's suggestion of plugging up the holes would work very well if this is a very nice, original car....