Just looking at one of my FLAC files and its metadata, tagged by SongKong (pulling from MusicBrainz), I see the following pertaining to dates:
<ORIGINAL_YEAR>1976</ORIGINAL_YEAR>
<ALBUM_YEAR>1997</ALBUM_YEAR>
<ORIGINALRELEASEDATE>1997</ORIGINALRELEASEDATE>
<Recorded_Date>1997</Recorded_Date>