I don't think so. In Lothlórien he had the protection of trees (as Legolas says in the Council of Elrond Gollum had become a masterful climber of trees and had learned to cling with both hands and feet to a branch). So he could use his sneak- and climb-talents to shake off the elves.
At the gate he would have no protection at all and I wonder if he was so sneaky that he could pass by them without being spotted. I don't think so.
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'You?' cried Frodo.
'Yes, I, Gandalf the Grey,' said the wizard solemnly. 'There are many powers in the world, for good or for evil. Some are greater than I am. Against some I have not yet been measured. But my time is coming.'
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