The county GIS would not be off by that much. You may be able to get a copy of the deed online if your county has them (the deed will have the legal description). In Alabama, some information is online and some is not. Visit your county website and look for probate records.

If not, get a copy from the landowner or from the probate court records room or department.

GIS is actually a tool for statistical analysis on data sets that have a geographic (location) or temporal (time) component. The maps that are generated with it are simply a visual representation of that analysis.

In the case of the county GIS, the map is both the visual representation of the relational databases that hold the information you can get by clicking on the map and the interface that allows you to access that information.