That’s in fact the most interesting detail so far spotted, it’s a construction number and if we are correct, it means Batch 03 aircraft number 70 (the second one had CB0369).
Just to remember: when the 1st Air Brigade unveiled its J-20As in January 2022 construction number CB0256 was spotted, now these are CB0369 & CB0370.
And since these two numbers are serial numbers 78130 & 78131, it must be reminded, that serial 78132 was identified back in April 2022. So assuming the 10 serials aircraft were delivered sequentially, it would imply this CB0370 airframe existed back in April! … and this means we eventually - to phrase is carefully - need to raise our number estimates of J-20As in service dramatically?!