No. The number on my times is 124T1952-1
Yes. The clock needs a neutral wire for it to work when the power output is turned off.
It does save and we also have the electric company auto-disconnect. I have the timer set to be on only 2-3 hours in AM and 2-3 hours in PM. Don't have current figures to quote, but checked it after first installing 25 years ago and it cut heater usage drastically then.
It's hard to say, I've always setup and used the water heater timer from the start. If I don't use the water heater timer, my electric bill will be high. It's worth it, to install the water heater timer, if you want to save money. Turning on the water heater, when you need the hot water, then turning it off. That's what I do to keep my electricity bill cost low. If you want to know the difference, check your electricity bill without the water heater timer. Then install the water heater timer to see the difference.
For us, it is not an issue of saving money. We are off-grid, and we only want the water heater to run during peak solar output at mid afternoon. This lets us control when the water heater turns on, if needed.
cause the timer is Crap , just install a manual switch
You need to follow your original wire connection, by taking a picture with your cellular phone to install the new water heater timer. It comes with extra tripper and pins, which you can hand tighten to the timer dial to turn it on and off. If, you are not sure about the wire connection, ask a electrician.
You need to try and connect it to see if it works, use the tripper and pins that come with the timer to set the amount of time, you want to set it.