Use target mode to pull data from a hard disk encrypted with FileVault?
Yes, 

Boot the Mac you want the data from into target disk mode, https://support.apple.com/en-us/HT201462. Connect the two Macs and wait. You should be prompted for the file vault password. After you enter the correct file vault password wait some more. After a few minutes the other mac's drive should mount on the desktop. Now copy over any files you want to keep.