I will look into that. But frankly, I'm not confident that this is possible. As far as I know, flipping is a hard coded mechanic. Not even the normal pumpjack supports it. And there aren't any graphics for this. And you can't just flip the graphics, because the shadows wouldn't fit. I'm also considering a mirrored variant as a separate entity, but I would still need new graphics for this, plus my brain scream "nooo" to this idea :)
If anyone with Factorio modding experience might have an idea how to do this, your input would be very welcome.
If you're ok with slightly asymmetric builds, this might be a workaround? https://imgur.com/a/uUEsxnP
BTW: If you are playing 2.0/space age, I don't think you need pumps on this. with the new fluid system, you only need them in really really long pipe setups.