In Blender 1x1x1 is 0.5 0.5 0.6 Blender Units.
I thought that was wrong.Or like something was wrong, you said that it was off like .00058054509494 points or something....
Couldn't you easily find the .dts formats of these in your Blockland folders?
They don't have models if I'm correct. They're .blb which is just a renamed .txt file with the dimensions and brick type written on two lines.
I'm quite certain the DTS files are the models for the bricks. Collisions you see.