I suspect it's in the morning, as presumably they would put 18:54 if it were referring to the time in the evening.
I suggest going out and purchasing several more bags of chocolate covered almonds (the larger the sample size the better) and checking the date and timestamps on each of those, to confirm whether or not they use a 24-hour clock system.
Of course, you'll then have to find some way of "disposing" of those extra bags too, but that's a small price to pay in the name of health and safety.