Do large (and larger) creatures drop equipment suitable for their size?

I noticed there isn’t an indication of size on the equipment of large-and-larger creatures. I’d assume they would drop weapons and armor corresponding with their own size, but the illustrations of some creatures depict them one-handing two-handed weapons, such as Stone Giant wielding a greatclub. Is there a hard-and-fast rule on the size of equipment such creatures drop?

Stone Giant