@Athanasius has created a lot of new texture files which are versions of previously existing textures, with added armour. You can download the pack from here:
http://piratesahoy.bowengames.com/potc/Grey Roger/Cuirasspack.rar
The filenames are all just numbers. You'll need to examine the files with TX Convertor and try to find a set which matches the model you want to armour. Alternatively, find any texture files which are the same layout as the one for your model; then use Photoshop, GIMP or your choice of picture editing software to copy the armoured parts from these files to yours.
http://piratesahoy.bowengames.com/potc/Grey Roger/Cuirasspack.rar
The filenames are all just numbers. You'll need to examine the files with TX Convertor and try to find a set which matches the model you want to armour. Alternatively, find any texture files which are the same layout as the one for your model; then use Photoshop, GIMP or your choice of picture editing software to copy the armoured parts from these files to yours.