There were a few (software) restrictions placed on the devices, namely that you had to have password lock turned on, and a password complexity policy. But after that they really did not interfere at all. When I left I reset that phone myself, and then bought a new iPhone and used the backup (not including OS) of that phone off of iCloud (of course minus the Apple email account they just turned off, and a couple of Apple-only apps I was using).
Other than some basic access controls on systems (especially around iOS sources), and a lot of prototype-asset-tracking (I ran a lab with a lot of that), Apple really does trust their developers to do the right thing. If they trust you to have the information, then they trust you not to share it without a lot of big-brother monitoring.
And there really is very little in the way of an IT department at Apple as you would normally think of it. They provided the network and the printers, but setting up your own computer was usually up to you and whatever help you got from your team (who really were the ones who knew what you needed for resources).