Yes same coin, poloniex is just being retarded not following the rebranding of the coin.
I used to use poloniex but... issues and zero support.
Make your life easier use bittrex.
But most of all use a wallet to store your coins, put the coins on an exchange only when you buy/sell.
New to XLM myself as of today, that difference also confused me, but alas did not yet have a validated Poloniex or Bittrex account... ended up using Kraken (from the US) which despite numerous gateway (cloudflare) errors, managed to get my XLM in the end. Frustrating experience though. Look forward to trying the other exchanges.
Got it in the middle of the pump this AM due to Godex news (without errors would have been beginning of the ramp), but having a cold needed a nap and missed the peak to double my stake, guess I'll be here and keeping a eye on this project for a while. Cheers!