You could also export each point group individually and assign a group on import. I would watch for dup points with this.
Are you sure you had them selected when you made the WBLOCK? Try opening up the WBLOCK dwg and see if there are any points in there. I know for sure that it has worked for me in the same way as you are trying to do it.
Credit where credit is due! Give kudos or accept as solution whenever you can.
If you have a point number-based group, you can drag and drop a point group from workspace of one drawing into model space of a target drawing. The definition will hold, points will not be copied.