[mkgmap-dev] how to replace false tracktype keys in style file?

I've noticed there are a lot of tagging mistakes have been made on OSM regarding tracktype={number} instead of tracktype=grade{number} Is there a simple formula (with regedit?) to replace this, like tracktype=1-5 > tracktype=grade(1-5) in the styles? At the moment I ignore those false keys but I would like to use this information instead of deleting it.