I should add that you can copy the names in many different styles, such as full path or filename only. Here is the full doc on that raw command:
COPYNAMES/O [<full>,nopaths,url,hash,hash2,hash3,unc,short,single,path]: This option copies the names of all selected files to the clipboard in ASCII text. It does not copy the files themselves. By default the full pathnames are copied but if you specify nopaths then only the names of the files are copied. If you specify url, the filenames will be copied as if they are URLs. You can also specify hash or hash2 to copy the MD5 checksums of the selected files to the clipboard. The output of hash is more readable, whereas hash2 outputs in a format compatible with the MD5Sum program.
Use hash3 to copy the MD5 checksums only, without the names of selected files. If single is specified and multiple files are selected, the filenames are copied to the clipboard on a single line separated by spaces, rather than one name per line as is the default. The path argument will copy the source path to the clipboard, ignoring any selected files.
This switch can also take the unc parameter. If you are copying the names of files on a network share, specifying unc causes them to be copied using their UNC pathnames rather than using the shared drive letter. For example, E:\Leo.txt may resolve to \\Work_Server\Drive_E\Leo.txt.
Specify the short parameter to copy the short (8.3) names of files.
I got this by opening the help with F1, then Expanding Opus Raw Commands and reading Clipboard.