Not necessarily. If they are butted, they would likley be 14 ga on the ends, but something different in the middle, which is what counts when measuring tension.

To OP, Assuming they are pretty standard spokes, until you get the gauge, here is a way to guesstimate the diameter using your eyes and hands:

1. If you can see easily that the last inch or so of the spoke on each end is thicker than the middle section, then you most likely have double butted spokes that are 2mm on the ends and 1.7mm in the middle. Use the column on the chart for 1.7mm spokes

2. If visually, the change in thisckness is not obvious, run you fingers slowly along the spoke, as you near the end, if you can feel the change in thisckness, then you likely have double butted spokes that are 2.0mm on the ends and 1.8mm in the middle. Use values from the chart for 1.8mm spokes

3. If the spoke thickness feels uniform from end to end, probably you have 2mm straight gauge spokes.