I believe they use laminated woods on all those ES semi hollows- and the center block is definitely mahogany- take a look at this- this movie is almost an hour long- takes a long time to load unless you have a decent internet connection- but well worth it. the shot of the spruce block they use between the center block and top answered so many questions I had. I think they mention that the Alvin Lee model has a maple block and some sort of cut out in it-I havent watched the movie in a while and I need to scoot off to work.
http://video.google.com/videoplay?docid=4764707652331081865
I think this has been posted before- there is also a pdf that shows this process- I think the link is www.upnorthstrings.com- there is a pdf on there- they use a modified center block- doesnt go all the way to the end of the guitar like the gibson does.
hope this helps you.
Peace
Natch