AKU = Adaption Kit Upgrade, which is essential like a Windows Update or Service Pack.
The phone lock and voice activation are programs built into the Windows Mobile OS and not a carrier specific program. If you don't have those programs you do indeed have an older version. You can check which version you have by going to Start->Settings->System->About. After the line that says "OS 5....." look at the last digits. That is the AKU number. Considering you don't have the device lock means you have a really (relatively) old version. Check here to see the differences:
http://www.mobile-review.com/pda/art...m-aku-en.shtml
As far as upgrading your AKU, unfortunately I just recommend you start reading the forums here under the Apache section. FYI, Apache is the general name of all the 6700 phones from the device's manufacturer, HTC.
There are a lot of ROMs out there now so it can be kind of confusing, but look for AKU3.5 releases. Considering you have such an old version, this update will make it seem like you have a brand new phone. I think you'll be very surprised the difference your experience will be with this phone once you finally upgrade.
Good luck.