I got their official reply: "You can still collect your race pack on the race day itself at the information booth from 6.30pm to 12.30am.
Kindly bring along your confirmation slip for collection. The information booth is located at the race village, please refer to the race map (athelete's guide) which will be available for download in May."
In SG, the most suitable route for marathon is the East coast park, will be quite boring anyway. I did my slowest FM in this race so far too...Weather is not runner friendly but glad that there was no heavy rainfall and thunderstorm.