not really, but I wouldn't say its light either. it looks like it was a table top at some point in its life. (holes in the back that look like legs were attached). I see a fair amount of Redwood on craigslist around here.
What ever it is,
You got a great buy at $22.00.
Work out you plan of attack and go for it,
Lets see the chips fly, and the photo's posted.
Congratulations,
Brian.
Looks like Redwood Burl. One sure way to tell for sure is to saw a small piece. Redwood has a very distinctive smell that even intensifies as it burls.