A reputable company will be bonded and insured.
Call the supervisor ahead of time and tell him you would like to know the names of who is delivering the safe.
That should be about the best you can do.
We had a sofa delivered before christman. Same worry. They saw my gun safe and all my animal mounts on the wall so it was obvious I was a big hunter.
The safe should be bolted or chained down anyway. So what can they get? Also make sure you keep accurate insurance and a list of serial numbers, Etc.