I'm not sure why you would see that? My blocks have dimensions in them, they are just hidden unless I am in "edit block" mode.
1. One of the points in the block is constrained completely.
2. another point on the block is constrained somehow for "rotation" constraint.
Then it should be fully constrained with your included dimensions.
Charles, let me clarify the behavior I see:
1. I insert a block into a sketch. It is grey, and moves as a unit; no dimensions are shown, as expected.
2. If I explode the block, there are no dimensions.
3. If I edit the block, there are no dimensions.
4. If I drag the block file into the Solidworks window, I get an empty part with a sketch that contains only my block. If I then go and edit my block, I can see all the dimensions. All the fonts and dimensioning settings are off, so I don't know what sort of state Solidworks is in at this point.