Placing survey pins in concrete would normally not be necessary. However, the discussions about the property line with the neighbor have me thinking it is a good step. I'd just leave the flags but he made a strange comment once about having a survey done before and then someone removed all the flags. The way it was stated it made me wonder if he did not move them as he did not like where they were placed by the surveyor.
Regardless, I used the post hole tool and dug about an 18" deep hole at each flag the surveyor added. I filled it with concrete and let it setup a little. Then I inserted the rebar allowing it to protrude about an inch out of the top. I left the flags at each pin so that I can locate the pins until I'm really familiar with their locations.
I've not done anything yet with moving the fence but it is still on my list of projects to complete. I'll probably get a few really long T posts and then put them beside each of the pins. I'll paint the tops purple and will probably tie the flags to them too. Then I'll be able to visually connect them even better as they will be taller. I'm not going to rush that project but will try to take care of it in the near future.