Unfortunately no. They are created on the fly be code in Fritzing so you would need to find and modify the appropriate source code which is usually a very difficult task (as the source is mostly completely undocumented!)
edit:
I am (slowly!) working on a python replacement for the parts factory (which creates headers and generic ICs and probably stripboards too) which will make this easier but it is going slowly (as I’m not a particularly good developer )
edit1:
Sometimes I forget what I have done. There is indeed instructions (fairly complex though) on making a custom part that is a strip board here
Peter