Welcome, Kim.
Nice looking machine. I'm sure I've seen one similar, maybe on QB, maybe somewhere else. I believe it is actually a National machine.
Unfortunately, the "Needlebar Picture Library" has gone AWOL so I can't peruse it to find one like your treadle. I
think it may actually take what is called a 20x1 needle. I think what you are referring to when you ask "Do you know if my 2019 schmetz needles will work?" is what is seen at
https://www.schmetzneedles.com/tag/15x1/ Technically, it originally would have taken a different system needle than what you are referring to.
Fortunately, many have found that by
not putting a 15x1 needle all the way up, one will still be able to sew with machines that called for a 20x1 needle.
Janey - Neat people never make the exciting discoveries I do.