2002 X5 4.6is Code P0720 need help

Hello everybody I came across this 2002 X5 4.6IS with 60,000 at work it’s a beautiful car and I really want it however it’s has 1 code P0720, I’ve done research on this code and apparently it’s the output speed sensor but I’ve also read that it could be a wheel speed sensor also. We have a test track at work that we can drive the cars down and I took it down and it shifted into every gear fine ( from
What I can feel no hard shifts or anything) I got it up to 50-70mph can anybody please help or enlighten me with potential problems or solutions and what else I should look out for. If I choose to get it I would only pay 1600 for it thank you for your time and help I can take more pictures of things going on tomorrow at work if need be