No, not all manual Civics come with a tachometer already installed.
I mounted mine at the pilar, so that it covered the AC/Heat vent. I've seen people mount it on the center of the dash before too. I had mine on there for a year and a half, and just took it off this past week. I used to see people who knew me, they'd drive up and know it was my car "because of the huge glowing tach in plain view". Personally I'll never put one on my car again, it's amazing how much more of a view I've got when the thing isn't in my way (or at least reflecting on my windshield). It'd be a better idea to sell the tach, and buy a gauge cluster that comes with a stock tach (Si, VX, EX, etc).