Removing coral from the plug is a general best practices imo as it limits the transfer of potential nasties into your tank.
On the other hand, given it is a new tank and it sounds like you may be new to coral, you may need to do some moving around of the corals in the tank, to get them where the light and flow are best. That is harder without them in a plug.
A nice hybrid is to dip and inspect your new coral, remove it from the original plug and put it on a clean plug. Use that plug or disk to temporarily mount the coral where you believe they need to be. After a month, when you're done making adjustments to location, remove from the plug, and hard mount.