In "Yukon Con" you can hear that Timon has two voices, one changing from time to time: his usual Nathan Lane voice, and his TV-version Kevin Schon voice.
Yukon Con can be found on the Disney DVD Around the World with Timon & Pumba.
This is Kevin Schon's first episode as Timon. His second is/are "Palm Beached/Jamaca Mistake."
In Doubt of Africa, there's one moment (when Timon is asking the tigress to help save Pumbaa) in possibly the whole series that Timon has all five of his stripes. The rest of the time he has three.