Trouble identifying and manual recharging dual tank softener

I'm helping a neighbor out with their water softener problem. They moved into their house and found the softener out of salt and brine. They are not sure if it was working or not. I filled the softener with a bag of salt and a couple of gallons of water and then tried a manual regeneration, but nothing happened. I'm trying to figure out the make/model of the unit so that I can get more information on the unit. I've attached a picture. Can anyone help me identify? Thanks! Jack[

The unit in the forground is an Autotrol 255 w/electronic timer and the unit in the back ground a Fleck valve, but could be a 2500, 2510 or 2750. The cover needs to be removed to determine which it is.

Thank you!!

Even if the cover is removed it will not say which Fleck valve, but rather a photo of the valve body or the part that is behind the metal plate that the timer and drive motor are on.
I say this because all three use the same motor, timer assembly, so no difference from the front.

The unit in the back might be an iron filter and not part of a two tank softener system. An iron filter would not have a brine line.