I purchased a 3DS model with quite a few components. Loading it into photoshop gave me a singlr layer model which you can take apart :-)) The suplier show me his model on 3DS wich was seperate Meshes. Is this a bug
Yes, if the 3D model has separate components it is possible to move meshes around with the specific Mesh tools found in the 3D Panel.
But without seeing the model they are selling it is difficult to know. Photoshop Extended is not a 3D modeling program, so what the supplier may show you might be different than what they export for sale. They might be showing off the model to show you the quality and what they export could be just a single mesh.