I see 168.019's on the web with 752's. I also saw this. https://www.buzzufy.com/blog/2016/12/03/omega-752-specifications-and-photo/
As we know the OVDB isn’t infallible. There may have been C-cases with 752s in them but you wouldn’t expect them to say chronometer on the dial if it doesn’t say adjusted 5 positions on the bridge - surely that would be fraud? (Unless they came with a certificate of accuracy, I suppose) However, the movt in OPs example is only ‘69/‘70 - it doesn’t even have the late 60s style rotor. I would be suspicious of any watch with the ‘wrong’ movt in it from this period.