No way to tell without digging a couple different areas and counting the number of grubs in a set space. Then you need to identify them to determine their food source/damage potential. Only then should you decide what/if to use anything. Most grubs this time of year are slowing down and getting ready to winter. A couple months ago was the best time to prevent damage to the lawn and get them young. Most have probably fattened up and remaining damage is likely low. But I'm not sure if your area has a delayed grub feeding (I'm in SE PA).

HTH

At this time of year I would not expect any further damage if there was any. If you kill them now you would be wasting money and killing other microarthropods necessary for healthy soil.