While you're waiting for Steve, here's what little I know...
- I don't think it matters which way the spring goes.
- It might be possible to install the delivery valve (pointy thing) upside down but it would require a lapse on the part of the installer.
- The delivery valve carrier has a groove suggesting that there's a top and bottom end. I don't know what the effect would be of installing a carrier upsidedown.
- I don't know how you can upset the internals of the pump by doing something wrong while replacing the delivery valve seals and o-rings.