Textures never do, you have to individually save each texture and put it onto each part of your gun
Meshes dont have textures or colors.
How do I save texture it from the blender?
You save the texture and upload it separetly. I dont know how to save the texture. I don’t use blender.
You will have to bake your textures in blender together so that they fit on an image that you can use. This website seems to go over it:
After it has baked go in to studio and press the View tab then look for the Asset Manager icon. Then choose bulk import (should be at the top) and select both your model (export it as an FBX, make sure to export after you have baked the textures) and the PNG image bake. If your model doesn’t have any problems it should load both items in. Also your image file and the model should be in the same folder on your device.