Okay, I just did a test run on a lot in which I built an enclosed yard and added the Celeb gate, and a square-box gutted temp house with only a front door. I cannot lock the gate in Live Mode, it still has only Open Gate and Close Gate options. Un-setting the house door as 'front door' does not allow setting the gate as 'front gate.'
However, after enabling testingcheats, and while in Build/Buy mode, and by holding CTRL+Shift and left-clicking on the gate, the option for 'Lock' was available. So I selected that. I also selected 'enable for triggers' or something similar, and then activated that, I was able to set the gate as 'front gate' in Live Mode. From there I could designate who could pass through the gate.
But I shouldn't have to go jumping through hoops just to get this feature to work, so if that Super-Patch @veiledstar so kindly suggested will fix this problem, I'll download it.
Thanks again, everyone!