I don't believe the LP series mini-bars typically came with mirrors. I have several that do not, however you should be able to locate an LP style diamond mirror and fit between the rotators if you wished.
Looking at your video though.. there is not enough room between the rotators to mount on currently.
It's possible a flat style mirror will fit, keep in mind that your mini bar uses the older LP6000 style rotators. The light in the video is using newer MX series rotators.