When I was 8 my father got me a guitar and sent me to lessons, it took about 5 minutes before the teacher took the guitar out of my hands and strung it upside down and set it in my hands left handed strung for a lefty. I played that way till I was in my mid thirties and laid a circular saw across my thumb and had to have it re attached. So about 2 years later when I decided to try playing again I took my 3 guitars and restrung them right handed and started to relearn how to play. The problem is I heard everything lefty and had to translate. I then took the advice of one of my teachers and turned off the lights and started to play the songs I knew by heart, no sight, just sound. Well I now play right handed finger style. I do not have the speed I had in the 90s hair metal days, but I can still keep my place up in a lineup. I think that switching to finger style has actually improved my playing and brought out a style I always loved to play, plus I have tripled my chord vocabulary being able to use triads while knocking out lead lines.
I think playing strung upside down is because someone never taught them different, I could have done it when I switched, but knew better.
those 2 left handed guitars, well 2 I have offed to collectors who paid me around 10 times what I paid for them and I am now about to replace the Tele, so I guess I am looking for someone to off it on.