I was reading about Ioun stones and the DMG gave them an AC, HP and resistances. I was wondering if regular equipment such as armors and weapons also have those stats.
Objects can have "stats" at the DMs discretion.
For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.
So, for the purposes of armour, each individual piece could have its own stats rather than the full set being considered one object.
Things like AC and Hit Points are determined by what the object is made of and size of the object. Rules for which can be found in the DMG, pages 246 and 247.
However, in general regular equipment such as armour and weapons do not have stats such as AC and HP.