At that scale, I'd bet that selling (even if buying at home) would be obvious to professional traders in the gold market. And quickly hit the headlines.
Which is exactly the scenario you'd want to avoid, if you were concerned that a certain President might decide that "your" gold, locked in "his" vault, meant that he had you by the bars.
You also need to build the infrastructure to take on 1,000 tons of gold. I doubt that's done in a month. IIRC, London has the biggest storage after NYC, so that's probably where it'll end up in the interrim. Eventually, I'd guess Switzerland will rise to do more gold storage.
We're essentially creating the same scenario as WTI vs Brent oil, where gold is partitioned into multiple different products depending on location.
Meanwhile Germany could silently buy gold at home and let the market handle where it comes from.