Though I can't tell exactly what model those J-7 are, but the three-piece windshield tell me that they are old ones. Doesn't PLAAF adopt the latest model of J-7?
... and they still fly those "B" while their latest model are "G"? What does that imply? Later and latest models are export only and PLAAF continue to fly those old "B" for fun!
Nothing strange in that. All air forces in countries with an indigenous aircraft industry will see newer models being exported of the planes they themselves have.
In China, production of J-7G stopped about 2006, since PLAAF is now getting J-10's from Chengdu. On demand production of tailor-made J-7G's is still ongoing, with 12 J-7BGI to be delivered to Bangladesh this year.
... and they still fly those "B" while their latest model are "G"? What does that imply? Later and latest models are export only and PLAAF continue to fly those old "B" for fun!
It implies that the PLAAF is moving away from the J7. There is little point in equipping a unit with J7Gs now when they are slated to get J10s or J11s in a few years time.