https://www.amazon.com/dp/B00006IDL6?ref_=cm_sw_r_cp_ud_dp_AZZBC3F9WMZ9C12GYV63
Might just have to wrap it over the hinge.
But in all honesty - I'd look into some residue free tape. I doubt there's something as niche as that for a niche of a product as the M16.
I bet even a wicked small round sticker would work fine.