first time posting, have a question about my HeartGold game

I def got a knock off copy from ebay, I accept that. I go to the game corner room or whatever, and the game shits the bed. My buddy has SoulSilver and we can still trade and battle (i'm pretty sure, we were in the same pokemon center and could boot up the talk screen to get to the trade). He's not sure if his is legit or not either though. My question is, can I trade pokemon from HeartGold to a newer DS game if it is 2 DSs in 1 room, with my HeartGold being a dud? Cause if so, I'm going to go full steam ahead in HeartGold, but if not, I don't want to waste my time training pokemon I can't carry over. I got really revitalized by the series, and haven't played since Red and Blue when I was in elementary school, and I'm looking to jump in, head first

Thanks