"You can bet if an engine failure occurred on takeoff they would have raised the gear."
In military test pilot schools, it is taught that you keep the gear down while going through all the other tests that must be done on first flights. As for what to do if you lose an engine on a first flight, they were probably pretty light so they might not pull it up even then. Just my thinking. In any case gear movement is a massive thing. The KISS principle applies. Keep It Simple, Stupid.