Normally you are correct, Volume controls are logarithmic or audio Taper but for some reason here they use a Linear Taper pot.
It might be hard to see in the picture but the part number is RV4NAY SD 103A
Yes it is Linear not Audio Taper. Most volume controls are Audio Taper. Either should work, just might make the volume range of the knob a little different but if you want the correct one then that's the number you need.