no dont lap it (wet/dry paper) as that will ruin the flatness. I dunno how flat yours is but mine was quite flat with only light scratches from machining, but overall flat. However the base was machined aswell as the top, to reduce the thickness.
Use 1200 grit paper but skip the rest before it. Then you need a cloth wheel, I think you can get them for dremmel tools, but I used a large 200mm felt one at work. then you use pollishing paste, I used 6 micron diamond paste and 1micron after, which gets it mirror shiny.
http://server5.uploadit.org/files/kbn2k3-wb1base.jpg
If you laquer it only do the sides and top. The wet parts of the block it isnt nessasary as it will be wet, so shouldnt have to much contact with air if you remove most of the bubbles but make sure you use distilled water.