Metal tags on tefillin, what are they?

I got these tefillin passed down to me from my father-in-law (who likely never used them) and they have these tags on them. I’m assuming the “כשר” just means a sofer checked them and it’s okay to remove them since I haven’t seen it on any other tefillin. However, I wanted to check here before removing them to make sure since it is kind uncomfortable to wrap them with the wire poking my arm.