There's a 1964 Lufthansa timetable page which includes their scheduled London C46 cargo flights on line here :
http://www.timetableimages.com/ttima...64/lh64-16.jpg
which shows that two aircraft were due both in and out in the early morning. However, it was common for certain cargo flights to be cancelled, particularly at weekends, if there was insufficient commercial load, or if there was the opposite, to run extras.
There were a range of Capitol C46s leased to Lufthansa over time in the 1960s. My records show regs N9890-3Z, and also 66326, 68966, 7923C, 5076N and 1312V. Capitol generally just kept the reg of the previous owner for its secondhand purchases, which these and nearly all of the rest of their fleet were.