I would think even at the factory if they restamped something they would use a very heavy strike and probably quite a few times to make sure the numbers would be seen clearly. Even "sharp faced" stamps hit repeatedly would bounce around and make it look like a "flat faced" stamp...
The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.
Even "sharp faced" stamps hit repeatedly would bounce around and make it look like a "flat faced" stamp... 