Got no idea, to be honest.
A side-question - do all your 20-47 wagons have interior/seats like that one which you posted? I mean, individual seats with textile upholstery? by any chance, was this interior initially built as a Ist class wagon? because our Ist class wagons from (more or less) the same age with yours do look quite alike quality-wise, whilst our 2nd class wagons are definetely lower.