I think Dennis might be on to something regarding the source of the data. Simulate Signal, for example, uses 0 as the initial timestamp on its signals, which will show up as 1904 as you noticed. If you do something like in the following VI, you should see current timestamps.
Now if your data is from an actual acquisition from hardware, I believe the timestamp should be correct, so none of the work in the middle to set t0 should be necessary.