I don't know where this 737 AT/AP story comes from, but I flew the classic with an Australian operator for 3 1/2 yrs and comp policy (not Boeing I know) allowed retaining it in without the AP and no problem. Must admit it was for the first couple of sims doing the endorsement (first jet), but after fine, and shouldn't be an issue for any jet experienced pilot (maybe an exemption for AB only types!).