You may want to run them through my part checking script available here:
which will happily complain about lots of things (and I am working on making it complain about even more 
). As well, if you want to modify parts in core submitting here is no longer sufficient. The only way updates to core are being accepted now is by making a pull request on the parts repository on github. Long term (after getting development working) I hope to go through and clean up all the parts in core. Many of them as you note are wrong. All help doing so is appreciated.
Edit: As long as you are changing things with the intent to change core could I encourage you to also rescale all the parts to be as called for in the parts file format? The instructions on how to do it in Inkscape are here:
Peter