The "Star of Life" is actually a federal US standard as far as the design goes but many shops just use mostly correct copies found all over the web. Look up Federal specification KKK-A-1822 and note: The Star of Life Symbol is a registered Trademark of the US Dept of Transportation. There is only ONE official and correct Star of Life and every state will accept the correct one since its actually part of the specification for a certified Star of Life ambulance. Hint: get the full PDF document and extract the Star of Life from it and then you know you have the correct and official one....
Also as far as the roof one goes, non-reflective 180c might be okay in some states but not all. Here in SC the regulation 601 states - All items in the section shall be of reflective quality and in contrasting to the color to the exterior painted surface of the ambulance. "Top (roof): There shall be a "Star of Life" of not less than 32" in height as well as the individual providers ambulance number of not less than 12" in height."
We actually keep the SC regs printed on the wall here since we decal literally many dozens of ambulances a year. There are always a couple in the lot waiting to be done here.