I don't know why people keep bringing up how slippery the SMB1 physics in Mario Maker are, because as someone who's probably played more SMB Deluxe / Lost Levels than 99% of the people in this thread, they're absolutely not the same as the original game's physics. I'm pretty dang sure that they all use the NSMB series physics as a base, as the others feel a little inconsistent (especially SMB1). For one, you aren't normally able to run over one-block gaps (without holding a jump button) or pull off the "unlimited 1-ups" stairs trick in SMW, and more obviously, you can't bounce high off of enemies in SMB1.
My experience playing the original SMB1 has come back to bite me a lot too, since its physics are pretty similar to NSMB's, but with about half the horizontal acceleration during any action; I've died a ton in SMM by trying to do what would have been a minor midair correction in the original, but sends me careening backwards in Maker.
So no, I'm positive that SMM unfortunately doesn't use proper SMB1 physics. Though I'm fine with them not having been used in any games since SMB1, not having them in SMM is pretty disappointing. IMO, they were fine in the original; it's not like they've ever been the sole responsibility for a death (and personally, I think the extra committal required for jumps in Lost Levels is what makes it the Lost Levels).