Bish has got you covered with the waffenfarbe.
Red would only have been used if the vehicle was issued to the Sturmgeschütz-Abteilung (assault battalion).
The pdf link I had posted earlier, if you scroll down to the bottom, there is an allocation list for the Stug IV:
A batch of 22 shipped on March 20, 1944 carries the remark "für SS-Wiking". This indicates that they went to 5.SS- Pz.Div. instead. It is still uncertain if SS-Pz.Abt.5 or SS-Pz.Jg.Abt.5 got them (Mirko Bayerl suggests these were fielded in SS-Pz.Rgt.5 and not SS-Pz.Jg.Rgt.5). No reference to them can be found either in the Divisional or the Regimental (SS-Pz.Rgt.5) History. Nevertheless according to [3] the 5.SS-Div. still reported 5 StuG IV on hand as late as Jan 15, 1945.
Even with the uncertainty, Panzerjager wore pink piping and the black panzerwrap.
Photos of the 17th SS look to have used of both black and fieldgrey uniforms.
Unfortunately, the white washed vehicle is identified as a Stug III.
regards,
Jack