Show us the DD Form 214, Dan, of your service.
That one might be harder to forge—my Dad’s, which I found for his funeral service, and from active duty service in the US Army in the mid 1950’s was reverse printed. The image has the normal paper background being black and the letters on the form appearing as white. It looks almost like an x-ray. Don’t know if the USMC had the same or not.
That sounds like the old way they had of making copies prior to Xerox machines.
My birth certificate is like that. Totally black background and white letters.
After WWII, it was common for soldiers to take their DD214s to the courthouse and have them recorded for convenience. They would look like that.