there are a few subtle differences in 2800cs gauges from 3.0cs
1. the most obvious is the numbers are beige instead of white
2. the redline on the tach is 6200 rpm instead of 6400
3. the speedo / odo gear is likely to be different from most 3.0cs due to a potentially different diff gear.
doesn't say anything about how they function - quite normal for the clock to have stopped working ... and whether the gear in the odo still works. hard to tell if the odo reset cable is attached.