Well, the dealer sold the 44Z. I talked with them and it turned out the engine was from another mower, so it was a used engine, but the original engine had been replaced. No idea how many hours were on the engine, and it probably wasn't a commercial engine either, so probably not worth getting. I told them I'm looking for a smaller, backup mower, and they have a few others they need to work on to sell, so we'll see what comes along.
I would say that's a good choice, I question it not being used commercially, my 2006 Gravely only has a little over 800 hrs and it has only mowed my neighbors lawn and mine, I traded neighbor a couple of rifles for it in 2017, when I got it it had 600 hrs, so that averages about 60 hours a year.
If you look at a mower try to get one commercial grade that has had 50-60 hrs a year, that will truly be non commercial.