The PRR never did own any dome cars. And, there were never any dome cars painted in PRR colors. As previously stated, there were NP dome sleepers which ran on the SOUTH WIND during the winter months; but, these ran in NP colors. (Interestingly, the CITY OF MIAMI on the IC also operated these cars, and the IC painted them into their own colors.)
B&O had dome cars which ran into WUS. Some were from the C&O CHESSIE (Budd built); but, they had a few others (PS built, with searchlights mounted on the roof). SCL also owned some of the ex-C&O CHESSIE cars; but, I believe that these only operated as far north as Richmond, VA, never into WUS (although they were originally designed to fit through the Capitol Hill tunnels to operate on the C&O).
The combined AMTRAK BROADWAY LIMITED/CAPITOL LIMITED operated a dome (ex-NP/GN/CB&Q variety) on the Chicago-Pittsburgh PRR for a short while (I rode in one).
Model trains exist for fun, and whatever the manufacturer thinks might sell. However, models and their various paint schemes do no necessarily reflect reality. (Ever see a Penn Central steam engine?) So, take what models you see with a grain (or several grains) of salt.