The Rule for wearing military medals is so broad that you can really wear them almost anytime

Every branch of service has there own Rules BUT they most say something like this...
The Marine Corps Uniform Regulation, MCO P1020.34G, says that decorations, medals, appropriate ribbon bars, or lapel buttons may be worn on civilian clothes at the individual’s discretion. Individuals should ensure that the occasion and the manner of wearing will not reflect discredit on the award. Miniature medals may be worn with civilian evening dress. For non-evening dress, miniature replicas of ribbons made in the form of enameled lapel buttons, or ribbons made in rosette form, may be worn on the left lapel of civilian clothes.

As to medals which you are entitled but were not issued while on duty.

The VA can not authorize or issue medals that is up to each branch. If a medal was authorized for a certain period or action and you were involved in that then you have every right to wear it. As an example. One unit I was with was awarded the meritorious Unit Commendation after I left and was discharged BUT it covered the period that i had served with the unit. it may not be on my DD-214 (or it might be) but if anybody checked they would see I rated it

In the big picture - (or at least in my eyes) As long as you are wearing what you earned and not acting like a US Senator -What are they going to do, take away your birthday... I gave up 21 of those between 1981 and 2002.....