To evaluate which SharePoint edition and products are installed you can use the following PowerShell Cmdlet.
(Get-SPFarm).Products
Use this table for GUID matching.
| 35466B1A-B17B-4DFB-A703-F74E2A1F5F5E | Project Server 2013 |
| BC7BAF08-4D97-462C-8411-341052402E71 | Project Server 2013 Preview |
| C5D855EE-F32B-4A1C-97A8-F0A28CE02F9C | SharePoint Server 2013 |
| CBF97833-C73A-4BAF-9ED3-D47B3CFF51BE | SharePoint Server 2013 Preview |
| B7D84C2B-0754-49E4-B7BE-7EE321DCE0A9 | SharePoint Server 2013 Enterprise |
| 298A586A-E3C1-42F0-AFE0-4BCFDC2E7CD0 | SharePoint Server 2013 Enterprise Preview |
| D6B57A0D-AE69-4A3E-B031-1F993EE52EDC | Microsoft Office Web Apps Server 2013 |
| 9FF54EBC-8C12-47D7-854F-3865D4BE8118 | SharePoint Foundation 2013 |