The file naming of the textures for the blocks is setup and arranged properly so that you can easily apply any wood or plastic or whatever you want texture. Just name your desired texture according to the texture name and replace the texture folder. Same for the bump texture as well.
For Block for letter 'A' the main texture name is-
At the same time the bump maps are for all the 5 sides for 'A' are-
The rest one side does not need any bump since the letter itself will be there.
The total vertex count for all the blocks is 10192 and Faces are 17660.