many times when someone has a piece of property surveyed they put up boundary markers
this makes it easy to see the property line and keeps people from having to re-survey later
government surveys for mile line or section corners are usually brass discs about 5 inches across with the info stamped on them
the boundary markers put up by landowners are only for reference
if one is missing or destroyed it does nothing to change the ownership of the land
that goes by the legal description
you just have to survey again
moving boundary markers to fool people into thinking your property is larger and not doing their own survey is highly frowned on