Sounds ok, just one correction.
The standard StuG Company at the time was 14 StuGs, three coy to a battalion and an HQ plt of 3 StuGs. This was probably downgraded to 10 StuGs the following year.
I doubt that it was organic, but rather attached. My best lead is the 228. StuG.Abt., which according to Franz Kurowski (
http://books.google.com/books?id=gLjglRX...&ct=result - page 38) was attached to 6.Pz.Div during Wittergewitter.
It is probable that the organisation above was that used by the formation, however it is possible that the divisional panzerjaeger formation possessed some StuGs, though it more likely to have been using Marders.