That is true if Chinese has no knowledge about aerospace metallurgy. When you don't have the fundamental research cost, you have lot of money to play with final product. Most likely these engines will be adapted for military where there is no risk of bad publicity.
Or they can always pull a proven Loral trick. Bid so cheap to lure one western engine maker to move production to China, build sloppy engines which keep failing, pressure builds up, they get tired and copy original drawings and specs. Oops, too late.