If the robot drops the objects for orientation: yes, it is allowed.
But keep in mind that after 3.4.2 they may not be removed afterwards(during the run) by neither a referee nor a team member, even if the dropped object is preventing the robot from continuing its way. Apart from that, I think the robot can drop objects wherever it wants.
If a human drops the objects for orientation: no, it is not allowed.
According to "2.1.3 Robots may utilize various maze navigation algorithms. Any pre-mapped type of dead reckoning (movements predefined based on known locations or placement of features in the field) is prohibited." team members are not allowed to give the robot any additional information about the field and features in the field such as the start tile.
// Fredrik Löfgren, TC & OC member 2016 / 2017