We have an ear mark that has been registered to our family name since before I was born. My dad says the papers are in the county courthouse. We don't use the ear mark now and if we decided to, I would definately want to go look it up for myself before doing so to verify it's standing. (anything pre-computer era is hard to find!) Perhaps there are internet sites with ear mark and cattle brands you can peruse through. State by state, county by county?