Your management should know that 2003 is not supported by Dell on the R720, at least not installed directly on the hardware.
It may work, but Dell will not have drivers to assist, nor will their utilities work for it, so you will need to install directly from the OS CD, slipstreaming drivers for whichever RAID controller is in your system, either using the F6 utility during Setup or using something like nLiteOS.com, then installing the relevant drivers (if they exist) after Windows is installed. It will also be 100% up to you to find the drivers and to troubleshoot any issues you encounter during and after the install. (Of course, I will help as much as I can, if I can.)
Installing 2003 as a virtual machine would be strongly recommended.