IF there is any substance in this 'rumour' it is anecdotal since the crash was at 0950 on the second sector and the aircraft had been on a night mail flight, so at the time of the crash I would suggest that a 'previous (unofficial) duty' 'putting the seats back in' would have been strictly illegal but probably not relevant in terms of duty time. It would be little different to an airline management pilot doing a days work in the office and then going off meek and mild on a night flight, which we know happens. Likewise where they 'spent the night' may or may not be of interest to the enquiry as would be their 'base' and HOTAC if any, and previous duties/rest. So unless your ?'source'? has different information, it is irrelevant and there are far bigger fish to fry. Perhaps if he/she has, you would be kind enough to pass them on? He/she has, of course, contacted the investigating authority with this information no doubt? It is for them to determine in the course of the investigation whether the crew were sufficiently 'rested' for the duty.