Is it true that when something is truly covalent it doesent have a dipole moment or net polarity ?

Yes, if by "truly covalent" you mean non-polar covalent. There's polar and non-polar covalent. Polar covalent compounds have a dipole moment and net polarity. Non-polar covalent compounds do not have a dipole moment or net polarity except in cases where a dipole is artificially induced.