Possibly, except that the men who are or appear to standing on the destroyer or the gangway(s) are all facing towards to the quay, as though getting off rather than on. Many do not seem to have rifles at all and that being so, one would expect such "spare" rifles to have been handed out to them for embarkation?
Possibly the collection of rifles from men who had done exactly that: picked up loose weapons or weapons not actually issued to them and brought them back? Those who have rifles don't appear to be turning them in; perhaps their issue weapons?
Anyway, it seems pretty clear this was Dover Marine Docks from the roofs shown:
Arrival of the Unknown Warrior at Dover Marine Railway Station at the Western Docks on 10 November, 1920 Stock Photo - Alamy
The apparent absence of officers or NCOs is interesting.