(O)D&D and perhaps AD&D1E and Basic D&D are old school. 2E is something like a lost edition and the skills/options/powers/etc stuff is more like an unauthorized playtest done on the customer's dime.![]()
Mechanically, I'd say absolutely. It's extremely faithful to and compatible with AD&D 1e.
I think it moved away from oldschool-style supplements, though. Its overall flavor wasn't old-school at all.
-O
This.
2e occupies a liminal space between old school and new school, IMHO.
RC

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.