LOTS of folks strip out that bolt head. LOTS more strip the threads as well putting it back in.
I would get a pair of vise grips and break the bolts loose first before you put allen or triple square or whatever. Those bolts are notoriously tight, and that is best case scenario: it could be that a PO got there first and munged up the bolts ahead of you (I am on my third wagon, and this one is due for new struts too). Once it is loose, it won't strip unless you are using a phillips head.
Take some time feeding that bolt back in so you catch the threads right.