I would really do as much as you can to research some installers before hand.
After replacing my dish yesterday with a new 3LNB myself, I was blessed with seeing the awful anchor job the installer did with my old dish to the brick. About 5 holes were drilled, 1 of which was used. A small expanding concrete anchor screw was used in the hole. I have no idea how that dish has been up their for so long and is still standing.
After spackling up the old holes the moron made and putting in 4 solid expanding masonry anchors and getting the thing to the point where you can hang off of it, i noticed they totally disregarded any type of grounding whatsoever. The cable is run from from the dish to the a switch with no grounding blocks in between.
If i knew who installed this thing i would find him and knock his head in. Some installers talk about forming a union when work like this is done? Are you kidding me? My dog can do a better job.
The best part was the four perfectly anchored threaded sleeves where the Primestar dish used to hang. Installed perfectly and a grounding block right before where the cable enters the house was just left there.
If you are able to, I would plan on taking out a lawn chair and watching every move the installer makes. Ensure he grounds it, and certainly ensure he does not make swiss cheese out of your house. Promptly ask all cowboys to leave and have a competent person finish it up.