I don't know about serials as proof, but as far as satellite imagery goes, multiple images of each of these airfields, over a span of several years show the following:
** anshan. alleged 1st division, 3rd regiment.
never more than 16 j8 planes.
** qiqihar. 21st div, 62nd reg.
never more than 16 j8 planes.
**Shenyang/Yu Hung Tun. alleged 16th division, 46th regiment. supposedly recon regiment.
Never more than 20 J8 planes. Interestingly enough, on every image there are both 4-5 j7 (probably jj7) and 4-5 q5 (q5l?) planes.
**FTTC
never more than 8 j8 planes.
** urmuqi base. 109th brigade.
never more than 18 j8 planes. (plus quite a few j7, more than just for training purposes)
** gaomi. 12th div, 35th reg.
never more than 15 j8 planes.
** shanghai base. 78th brigade
never more than 23 j8 planes, and even that was back in 2006. two more recent photographs show 13 j8 planes.
** shanghai base. 93rd brigade
this is supposedly recce base. never more than 8 j8 planes. interestingly, it also repeatedly features quite a lot, about a dozen, of j7 and q5 looking planes.
** foshan. 2nd div, 4th reg.
never more than 18 j8. again, both a few q5 and j7 looking planes as well.
** dingxin. 14th base. test center
never moer than 16 j8.
Now for PLANAF bases:
**jiaozhou. 5th div, 15th reg
never more than 12 j8 planes.
** lingshui. 9th div, 25th reg.
never more than 16 j8 planes.
I will repeat once again that these are not just one off images. Each of these airfields has a few, sometimes as much as four different images from different times and the numbers are either less or as high as mentioned. I find it highly unlikely that on so many different occasions a good deal of the squadron was removed from the apron, for whatever pruposes. Yes, planes do fly and they do go to maintenance but at least 95% of the time they sit on the apron. (or in shelters, but here there werent any shelters.)
There are way too many j7 bases to do this but from ones i did check they too seem to feature closer to 24 combat planes than anything else. (maybe up to 30 with training conversion ones)