I didn't think there was too much of a difference between 70s Prairie and present Prairie, but I can listen again and do some comparisons. I can imagine the Letter game show was one of Prairie's earlier appearances since now she's a lot smarter and surely would know about the letter E.
Okay. Here's an update. I watched "What's My Letter" online and then listened to the above clip with Stephanie as Prairie and I have to disagree. I think Steph's Prairie comes closer to later Prairie than early Prairie, but oh well, everyone is entitled to their opinion.