Hmm. I guess it depends on what we mean by “small”. Like if hypothetically they increased composite share or improved some other structural aspect and shaved off 2-300 kg from an accumulation of small iterations is that small or major? That’s purely a hypothetical of course, not suggesting they did anything like that the J-20A, but curious to gauge and qualify these sorts of things.
I doubt there would have been widescale use of new manufacturing techniques that weren't already present in past production batches, and I doubt there would have been any change in weapons bay dimensions, as alluded.