Nope, the player is always going to the right in that segment. Here's what happened:
1. Midway through the jump, the player starts pressing left to slow down his momentum.
2. He's still pressing left when he touches the ground. As a consequence, Mario turns around as soon as he lands.
3. The player then jumps toward the Bob-omb while still facing left.
Now here's the difference: NSMBU Mario
would turn around in mid-air to face the new direction. SMB Mario, on the other hand, retains the direction he was originally facing until the end of the jump. It's a very minor graphical difference, but it's tricking people into thinking the jump itself is different. What we should look for instead is the height, length and momentum of the jump, and that appears to be exactly the same as far as I can tell.
*puts down the magnifying glass*