Well 2e had some real division in it back in the day.
I know of 2 major 'breaks' atleast here in CT, and one funny one.
I know that there was atleast one 'edtion' of the phb for 2e that had diffrent weapons and non weapon profs in it, but I belive it is a miss print (no broad sword, diffrint two handed sword damge vs large creature, and a scholor non weapon prof, but herblism and something else changed who got it)
The major breaks that effected me and mine though was:
1)Revised rule set made -10hp set as a defualt death instead of an option, and changed 1st level hp to max instead of rolling. It also changed the wording of Backstab (to this day there is a fight as to weather that was a change in rules or a clarfaction of language). A hand full of spells got rewriten, and Bardic Lore got changed.
(((To me this was the first time I would have to buy a new rule book, and I refused, it was only becuse the raven loft book "domains of dread" had a PHB lite in the back that I got away with it, so I used that.)))
2) We had pick 1 or 2 things from other books for our worlds (Kits, Barbarians, Ninjas ect) and used combat and tactics. However a ffew of us went to play a Dragon Mountin adventure box set with a new DM, and got hit by "we play 3rd edtion rules"
What that DM called 3e was, 12 attributes (each one split in 2 and had to e within 2 of each other) build your own class with points (what your thac0 what your special adilities where, what your spell progrssion was), choose a base race, but spend points on that too. Psionics with Mthac0, and spells could be mana or perday.
To be honnest none of my group ever played, the rules were too diffrent for us, and we just went back to our revised game.
(((((Funny note: I know that group had changed ro 3.5 and called it 5e, I wonder what D&D next is to them since I no longer see them??)))
I started with a beginiers box set that was for 2e, it came with a 3 set of adventures around the city of Freedale, and the wizard Nethril, it was a weird strip down Forgotten realms, and it had easier to play then 2e rules, so that might be yet another hidden edtion