These are FSX dds 32-bit textures only. The HTAI C208B model is required. It can be found at http://htai-models.com/downloads.html – http://htai-models.com/downloads/models/ai_cessna_c208b_grand_caravan.zip
The HTAI Cessna Grand Caravan model has been updated by Gavin Cole (gavinc), Graham Eccleston (ggeccles), & Tony RD (peluso5) from the AIG Forums to adapt them for use in FSX and P3D.
Get the model here: http://www.alpha-india.net/forums/index.php?action=dlattach;topic=24672.0;attach=44243