Re information on 1860s passenger lists ....
Imagine you are in a queue of people, with your 'carry on' luggage beside you, and your 'check in' luggage being loaded onboard.
What info did you need to give to obtain your ticket and what proof did you provide to substantiate that info ? ....
Well, back to that queue of passengers .... You arrive at the table where there's the clerk/s from the shipping line. They have been writing info into their records in long-hand, they are tired, they are hoping to also find passage to Queensland on that voyage, and they are rushing .... the ship's master wants to leave shortly, as soon as .... the tides/currents are favourable. The passenger has his ticket, bought earlier that day at the ticket office. The clerk there was interested in collecting the fare, rather than in finding any reason NOT to sell a ticket to the prospective passenger.
Those shipping clerks at the table are not from the same district as Gordon, they have different accents from him, and they rush their questions and they don't listen carefully for his answer. These informant driven lists are completed by those shipping clerks. The lists (Manifests ? ) are facing those shipping clerks.
Can Gordon read shipping clerks' scribble 'upside down' (afterall, those clerks have their paperwork facing them, not facing the passengers)....
So, while it is possible that Gordon MAY have needed some 'POI', (Proof of Identity)it is also likely that any requirement was not regularly checked, or inspected etc. Such POI may well have been a baptismal certificate rather than a civil birth certificate, and his marital status may well have not ever been asked by those shipping clerks. I can assure you that he would not have needed a passport. I can also assure you that 'labourer' may well have been the general description for any male who did not have professional qualifications .... and therefore it may well be that a 'clerk' without formal qualifications would be referred to as a 'labourer'....
JM