I have posted re: this very issue AS IT PERTAINS TO TRAVEL IN THE USA on several occasions. A general search or a search of my posts will find the threads.
TSA locks are permissible. That has been verified at many airports and in personal conversations with a TSA Special Agent and on-site TSA baggage inspectors.
I travel regularly in the US with a gun in my checked baggage. Though airport procedures vary a bit (in some airports you accompany your bag to the TSA inspection site; in others you do not) my gun is always in a hard-sided Samsonite suitcase with built-in TSA combination locks.
Just three weeks ago I was flying from PIT to CHA. At PIT you personally convey your suitcase from airline check-in to the TSA site. At CHA, the airline agent takes it to the conveyor that leads to TSA.
There was nary a problem(s) at either location. The same has held true as I have flown to/from these other cities, also, within the last couple years: Baltimore, Washington National, Charlotte, Hartford-Springfield, Orlando, Denver, San Francisco, Phoenix, Key West, Honolulu, and Kahului,
Be sure, however, to check with your airline carrier particularly if it's a non-US carrier and presume you have addressed all legality issues for your foreign destination.