If its j-15, its probably the second one. the first one already got painted.
there is snow on the photo. Probably its in shenyang.
Ohh ... so it's most liklely an older photo !
Besides that I don't think that the grey one is the repainted first prototype. IMO we have now at least thre - more likely four - J-15:
- the first and second prototype both powered by Russian AL-31F ... &
- at least one additional grey one - IMO even more likely another forth aircraft, which was seen behind the first grey one - which is clearly powered by the Taihang.
As such I really don't think that they reengined the first one and painted it.
But these are only my 2 cents.
Deino