There are some tiles in the L2 Classic tribe that are not part of the L1 Pillar set, such as some unique wood pieces and steel pieces. As such, these should be officially added to the Pillar tileset before the next NeoLemmix update comes out.
Included in the ZIP are all the pieces that are part of the L2 Classic set. classic_17.png, classic_40.png, classic_42.png, classic_45.png, classic_47.png - classic_64.png and some others I may have missed are the unique pieces. I found these from Geoff's Lemmins.