Yes, Vne, which corresponds to Vmo (speed for maximum operation) will always be in IAS, not TAS. The report you refer to was perhaps referring to an aircraft which also had a Mach airspeed limitation (Mmo). This will still be indicated as an IAS with a moving "barber pole" pointer on the airspeed indicator which tells the pilot where the maximum permitted speed is in those atmospheric conditions.
Vne for GA aircraft is derrived from a number of factors, flutter margin being one. This speed will have a margin of safety of 1.1. For several very good reasons, you should not be deliberately flying an aircraft at these high speeds, flutter is one, upset and overloading due to gusts are others. Below Va you're safe from both of these, above Va, your piloting skill is required to maintian structural and overspeed safety (not to mention what such speeds can do to the engine and prop with carelessness).
That said, 110% of Vne is tested for every certified aircraft. It is something I have to do during every test program - very carefully!
