Yes thats true.
Using properties you would have to go this way
entity.Position = new Vec3( 1,2,3 ) ; // C#
entity.SetPosition( Vec3( 1, 2, 3 ) ) ; // C++
Edit:
In C++ you could have Position Vec3 as a public and then use a Vec3= operator
Then you would have almost same as in C#
entity.Position = Vec3( 1,2,3 ) ; // C++