It is dead easy to take a look, almost no dismantling required!
Loosen the clamp bolts on the stem until they move freely. Undo the top cap bolt. If there are any spacers above the stem lift them off and set them to one side. Lift the bar and stem assembly off the fork steerer and let it dangle. Set aside any spacers that were under the stem. Hold the bike by the top tube and lift a few inches. The fork and its attached wheel should stay in place and you will be able to see the bottom of the fork where the lower bearing would fit. Compare that diameter with the diameter at the top of the steerer and you will get your answer. I will be astonished if it is not tapered.
Re-assemble, just make sure that you get the bars at right angles to the wheel.
PS: don't do as I did and do this with the bike on my workstand with the front of the bike a few feet off the ground. When I undid the top cap bolt, the front of the bike fell off! I can remember my shock even now!
PPS: While the bike is in this position, you might as well clean up and regrease the headset area.