I read once (believe at the Robinson Helicopter Owners Group) that RHC doesn't supply them _any more_, it was mentioned that this was maybe for liability reasons. Not sure if this was indeed exactly true. Maybe they never did, and it's something dealers add?
At the safety course they explained how these gages work, and said that they are pretty accurate. They actually said that using dip sticks might make it unsafe, because you may damage the fuel senders with the sticks, introduce other stuff into your tanks, etc etc.
I flew lots of R22s with home made sticks, but also saw these T-shaped ones mentioned above. Maybe it's time for another after market product. On R44 however, I've never seen any of these dipsticks (didn't fly many different R44's though).