"IDENTIFYING MAGIC ITEMS: A character can only identify the exact type of item by testing it (trying on a ring, sipping the potion, etc.)."
B/X doesn't have an Identify spell (which makes a nice gap for a magic-user to research a new spell). Sure a magic-user or cleric can cast Detect Magic but that even just ups the tension and suspense. Should you try the new magical chainmail you found? What does it do? Sure it might be chainmail +3 but it also might be cursed chainmail AC9... a BIG difference!
I think that one of the reasons why magic items have lost the "magic" in recent editions is it is either too easy to identify a magic item without risk or, even worse, players are just told what a magic item does up front.