Internal audits are to be conducted at every opportunity. In fact, you probably already do if you are in a supervisory or management role. It is always good to validate, verify and find opportunities for improvement. This, precisely, is what auditing is for and it pertains to everything, every situation, every engagement, every industry, everywhere.
By all means conduct an audit before a management system is officially endorsed or launched by the top management. If you do not, that is a non-conformity already even if any standards indicates that it is not.