Having unfortunately dealt with many repairs companies over the years I now make a point of photographing a part from all angles and capping any orifices securely before sending stuff away, I then put copies of the photos in with the part.

This doesn't stop any problems but it ensures you are both aware of the condition of a part before it is touched by another company.....

Of course this doesn't matter when the part is hand delivered to the wrong company and then the guy who delivered it can't remember where he took it to. cost my previous employer about 3 grand to replace the missing part !!!, A JCB hydraulic valve block.....