First of all, check the weight. A genuine 89-CC will weigh 26.73grams or very near depending on wear. Look near the mintmark for any signs of scraping or scratch marks. This should throw up a red flag immediately. There are added mintmarks from the common 1889. I'm just very cautious when it comes to key dates such as this. I would stick to a coin already certified by a major
TPG to eliminate all the doubts. That's my advice.