Are you saying that B/X does have magic resistance?
EDIT:
In B/X, Dragons have breath weapons (which they use a random % of the time), flight, three attacks (claw/claw/bite) and a % chance of speaking, which in turn triggers a % chance of spells.
Of the items on your list, they lack guaranteed spells, blindsight, wing and tail attacks, spell-like abilities (except for the Gold Dragon, which can shapechange), DR and Spell Resistance. I don't think they have immunities either. Their physical attacks - especially their claws - are very weak. It is only their flight and their AoE that gives them "solo" capabilities. They are highly vulnerable to action denial (typically from MUs using Charm or Hold Monster).
In 1st ed AD&D, dragons are very similar to B/X except that they get very modest elemental damage resistance (but also, from memory, vulnerabilities: a Red Dragon, for example, is -1 per die of damage from fire but +1 per die of damage from cold), a more generous process for calculating saving throws (as if HD = hp/4), and (I think) blindsight. There are no guaranteed spells (except for gold dragons, I think), no wing or tail attacks, no DR, no magic resistance and no immunities. The only spell like abilities are dragon fear, which has a HD cap on its effectivness, and the ability of silver, bronze and gold dragons to change shape. Claw damage is still pitifully low. As in B/X, it is primarily their flight and AoE that gives them "solo" capabilities, though they are less vulnerable to action denial, because of their better saving throws than other monsters of the same HD.
2nd ed AD&D introduces tail attacks, wing buffets, etc, and ups the claw and bit damage. It also introduces magic resistance for dragons. I think damage reduction comes in only in 3E.