Not a problem to do. If symaccess detects that the device is already mapped to the ports it will skip mapping it to the port(s) that the device(s) are mapped to. If you remove the devices from the SG and add -unmap it will unmap the device(s) regardless to whether or not they were mapped with symaccess.  Using both can lead to mapping devices to ports that they are not masked to but wont really cause any problems other than excess mappings.
Does anyone know the repercussions of running symconfigure and running symaccess to map the same tdev?
Classic Symconfigure and Symaccess ran on the same tdev