I've heard several versions, but here is a short version of how Paul ended up with his first cavern bass.
That's the only story I know! His first Höffie (an American bass would have been unaffordable for him, the tariffs were prohibitive to protect the resurgence of post-war Germany's industry) was a righty - as it should be, I don't think that left hand Höfners even existed in the late 50ies/early 60ies, certainly no one would waste money and stock them in a shop without a pre-order. Let's face it, in the late 50ies/early 60ies, lefties were expected to adapt to righty. When I went to school 1st grade in 1966, it was the first year where lefties were no longer "retrained" righty. It was a big thing, labelled as "a field experiment" of the education board, the principal would visit classes and assess how the poor lefties were doing with their "predicament".
The music store in question is very much your typical musical store you would have in larger cities (starting with a population of say 100.000, Hamburg was 1.8 million people in 1960, making it huge by German standards) in the 50ie/60ies.
I've also read that the lightness of the Höfner appealed to Paul as The Beatles would play up to 6-8 hours every night (up to the early morning hours, the Hamburg red light district had no curfew) six days a week during their Reeperbahn stint. You wouldn't want a P-Bass weighing down your neck and shoulders for that amount of time even if you are on a Captagon diet.
The part they missed was that Höfner had - admittedly so - ripped the violin shape off the Gibson EB(-1), albeit hollowing it out and using readily available German woods rather than hard to get and expensive overseas mahogany. Of course, the huge EB sales -
- did not spawn immediate action by Gibson.