Yeah. I think the reason behind that was most likely because has been stated as being 3 1/2 years old, so when TSWLO came out, they used the continuity that mathematically determines that Elmo wouldn't have been around before the year 2000 which in reality he was. Still that's a big mistake on their part. If they wanted to show SS before Elmo existed they would have had to go further back, like to the Matt Robinson/Orange Oscar/Bullwinkle Big Bird years. Or they could have just stated that these things happened when Elmo was younger. That would have made more sense.