When my wife did her interview back in 2018 at the embassy for her K1 they did ask for the I-134 and my current paystubs/ tax transcripts. We had already sent them with Packet 3 or 4 when we made the appointment, but the officer did look at them and hand them back to her. Maybe just comparing originals to what was sent in? Who knows. I sent her with just about anything they could possible ask for. was it a little overkill, maybe, but had no issues and a rapid approval. I would say to take them so you have them in case they ask. You don't want a 221g and have to delay things for something that is easily covered at the time of interview.
Hi, just updating my status for any of you who are waiting for your interview date. Our case was DQed at the NVC on June 15 of this year and we just received an interview appointment letter just yesterday. So don't give up hope, the process is moving along.