The Ringside issues were really the last 'full and proper' boxing card set we've gone. The 2011 Gold's are said to be /9 and the 2010's /10 (less often) or to /9 (most commonly) depending on the source from the time of issue. They are not serial though, and are a good example of why cards should be serialized if they are said to be done in small print runs.
This isn't true though. For example, pulling a random card, there are 5 of the 2010 #34 James Jeffries on COMC, another 1 on eBay, and 2 in my collection I bought just last week. This is in no way unusual, there are often 5-9 of a particular card on the market at any given time. Cards /9 from over a decade ago are very tough to find. These kinds of cards flood the market when they are released and then go into collections and become difficult to ever find again, even if not expensive at all because the people who bought cheap low numbered cards wanted those cards and have low impetus to sell them. The odds that 50%+ of the print run is available on the market at any given time is close to 0. These are by far the most common /9 cards ever released.
Hell, there are 17 Lennox Lewis #55 Golds on COMC alone right now. Impossible if they are numbered to /9. Here's D&A's listing that has the original marketing text advertising the gold base parallel cards as /9:
https://www.dacardworld.com/sports-c...xing-hobby-box
The people selling them and labelling as /9 are probably not being dishonest as this came from the original release announcements and marketing material, but I think it should be noted that this claim is clearly not true and somehow there are obviously a lot more than 9 of each card out there. I don't know if the extra supply comes from backdoored cards, or selling excess stock after the release, or if the maker straight up lied, but it is clearly present today. I know this set isn't popular but it should be noted and I haven't seen it said anywhere online.