Hi Chris,
I think it is very difficult to answer this question in general.
First off all a lens design must not be the same, just because both lenses have the same focal lenght. So it could be (I just do not know), that both lenses (the Rollei one and the Contax one) are totally different.
Secondly there are over the time improvements in lens design/ coatings and production enhancements, which can affect image quality.
Third, there is a difference between a lens with Zeiss design and the name Rollei on it and the same Zeiss design with the name Carl Zeiss on it. The different name on it tells you, that the lens was manufactured/ controlled by Carl Zeiss (with the Zeiss name on it) and by Rollei (with the Rollei name on it). The lens design might be in both cases from Zeiss, but it is coming from a different factory.
But this does not mean, that the Rolei one is worse. It is just a clear differentiation where is what coming from in terms of design, production and quality control.
The best ex&le is the Planar 80/2.8 PQS for the Rollei Medium Format. This is NOT a Zeiss production, although a Zeiss design. It is a Rollei production and under Rollei quality control. That is , why it is named "Rollei Planar" and not "Carl Zeiss Planar".
Do not mix this with HFT vs. T* coating. Both are almost the same - at least no difference that you can see in your final prints - according to the homepage of Carl Zeiss.