PTY-LAX/SFO and PTY-ATL are consistently MAX with lie-flats. PTY-ASU is typically 737-800s, though I've had a 7M9 once on that route. They are now starting to run 7M8s as well, which have American Airlines style seats up front, which are actually worse than the newer 737-800s.
Summary is unless LAX/SFO, I wouldn't count on it.