Not without interrupting service. If you can interrupt service, the cleanest way is to get the startup-config files from both boxes and cut and paste the data you want from one file to the other. Then transfer the startup-config file back and reset.

You COULD try coping the new startup-config to running-config, but that still causes a (shorter) service interruption.

To add new services without interruption, you are stuck with the interactive configuration and the y/n prompt, to the best of my knowledge.