First, welcome. UK police spec bikes got the 'S' type forks with integral brace before the 16-Valve models because the un-braced versions blew seals so often. I don't think that any police force in the UK had a policy of holding back bikes, it's more that bikes (and cars) were batch purchased and only registered when they were needed. Sometimes this might be as much as a couple of years later. As for the ABS, I doubt that it was removed by the force in question. The only issues with police-spec ABS bikes occurred early in the supply. It was found that the police radio could trigger the ABS. All ABS equipped bikes were recalled by BMW and modified to prevent this but they retained the ABS. Your bike has been fitted with the very early K100 seat and tail unit with the pillion grab handles in the seat as opposed to the tail unit.