Payroll services company ADP demonstrates that you don’t necessarily have to choose between using a flag icon or using a globe icon on your global gateway.
As shown below, the company uses both:
And here is the Brazil home page:
I don’t typically recommend using both a globe icon and a map icon. I believe a globe icon alone is sufficient.
But if you have to choose between using neither or both, choose both.
For more on global gateways, check out the book.