Morgan wouldn't just take advantage without giving something of equal value in return. If it's a unique item, immeasurable in value, he would pay far more than its worth in return.
For people like Morgan, money is not an issue, but they wouldn't want to owe someone a favor lightly. Gao Yang was already used to this.
Gao Yang pondered what he should ask for. An antique gun, even a particularly famous one, would at most be worth tens of thousands of dollars. Works like those by Denechal might fetch a very high price, but antique guns aren't mainstream art pieces like paintings or sculptures. Even at a very high price, they might only go for one million US dollars, perhaps two million at most, but no higher.
Money, Gao Yang didn't want it. After some thought, Gao Yang felt it was time for him to start collecting things that interested him and were appropriate for his collection. What he wanted most right now were WWII-era guns.