The answer is an unqualified ‘Yes’ but it is certainly easy and understandable to think otherwise.
Actually folder names follow the same naming conventions as regular files and can have extensions. The official Windows File System spec puts it this way, everything after the last dot is an extension. $RECYCLE.BIN being one of the most common examples:
However it is easy to think that folders don’t have extensions for two reasons:
1) Most folders don’t have extensions (or a dot (.) in their names)
2) Windows explorer defaults to displaying folder names (and filenames) as one unit so that the extensions aren’t highlighted.
Show the folder name as in Windows Explorer
This second point can be easily emulated in FileBoss.
Right-click over a column header and set up the small menu as shown below. Be sure to click the button before exiting. (You may have to do this twice, once in a normal explore tab and once in a Search Results (Virtual Folder) tab.