You can into sone countries take an unlimited amount of bullion. IN most countries you enter, you are llinited to cash and negotiableinstruments of $10,000 USD or less, or you must declare. Ify9u try to depost a cash or such negotiable instruments at a bank in excess of ten grand, they will refuse to take it without a customs declaration form.
One can electronically transfer millions of bucks across national boundaries between banks without ANY of this problem. Go figure.
If one declared the face value of the gold coins, which is significantly less than their actual value I don’t know how the Feds could do anything.