Holiday Tradition: Ornaments as a Gift

For our first Christmas together, one of his gifts I gave Johnny was an ornament that was representative of our past year together. It's become something we do every year. I look forward to finding one thing that will mark the past year, and he looks forward to seeing just what moment I've chosen to hang on our tree. 

This year as we hung each ornament we realized that 2010 seems to have gone missing. What's worse is I can't even remember what ornament I had gotten. I'm holding out hope that it'll show up when we bring all the boxes back out to pack all of our decorations back up. If not I may need to do some post-holiday ornament purchasing. Is it wrong to replace the 2010 ornament? Will it even matter 20 years from now if one in our collection happens to be a replacement year?