Yes...
I've got an idea about that.
This was very regularily ordered for (e.g.) Germany-delivered cars. It means everything prepared for the addtion of a radio but without the radio itself.
This 53/3 contained the interference suppression kit (i.e. electrical background noise suppression), best seen on the spark plug conectors with their metallic sheath or the additional condensors on the generator, etc. Furthermore, the speaker and the antenna (always) on the right front fender was already in place.
Only the radio was missing (the beloved radio deletion plate in place).
Becker radios were expensive at that time; around 480 - 580 German Marks (probably equivalent to 1500 - 2000 $$ today), so, many prospective buyers preferred aftermarket radios, especially Blaupunkt, which were way much cheaper than Becker.
US-delivered cars were mostly delivered with Beckerradios in place - from what I understand.
All pagodas have power brakes, it means the brake booster - which was still not so common on cheaper cars, at least not on the lighter Volkswagens, Fords, etc.
42/6 means power steering and automatic transmission with tunnel mounted shift lever.
Pagodas always had tunnel mounted shifters; column-mounted shifting (like on my 114 sedan) was not an option for the W113.
42/2 means power steering and manual gear change and 42/- means no power steering :'( :'(
Best,
Achim
(data card freak)