Changing Serial Number on working Hackintosh

Hi Guys,
I'm about to follow a guide to get Imessage working and it suggests redo-ing your serial number, uuidgen and board serial number. Am I ok to change them using the config file if I mount my EFI partition or do I have to reinstall Mac to change the board serial number? Will it mess any programs or anything up if I just edit the config file?
Thanks guys!