The basic, meterless Autocords were I think essentially the same throughout the camera's production run (mid-'50s to mid-'60s), though I think the later ones had a fresnel screen to aid focusing. (I don't think any TLRs from before the later '50s had fresnel screens.)
The metered Autocords originally used selenium meters, which were hidden under the camera's nameplate. I've never seen one of these in person, but I suspect that in low light or indoors you would flip up the nameplate and in outdoors situations you'd keep it down -- the nameplate has slots that let enough light in to make the meter work. Those meters could well be dead by now.
The Autocord CDS models (which used a rather large PX-1 battery; looks like a gumdrop) looked different from the other Autocords in that they had two rather prominent bugeyes where the nameplate would otherwise be. One is the cap for the battery; the other is the meter cell. "minolta" appears in small type between the two bugeyes and "AUTOCORD" appears on the top of the meter assembly. None of the metered Autocords had a coupled meter -- you have to transfer the reading from the meter needle (in EV) to the shutter and aperture settings around the lens. This is one place where the metered Rolleiflexes and the later metered Yashicamats are better.
At the time the last Autocords were being made, I think Minolta offered both the meterless model (which they called the Standard) and the CDS model in 12 exposure and 12 or 24 exposure versions. The switch for 12 or 24 exposure film is on the right side of the camera, by the winding crank. There's a further model distinction -- some of the last Autocords had a special stud for attaching a dedicated strap, as opposed to the slot through which you can mount a standard strap. The dedicated strap is extremely hard to find, in my experience. I've been looking on and off for years.
You can spot the last Autocords by the Minolta logo -- it's the lower case "minolta" such as you see on their SRT line of SLRs. The earlier ones had "Minolta" on the nameplate. All the Autocords used the same lenses, I think -- a 3.5 Rokkor that is really first rate. Also, all had the same film transport mechanism and focusing lever design.
The focusing lever is the weak point of these cameras. It slides from side to side underneath the lens plate, but can be stiff after 40+ years, and will break if forced since it's made of soft metal. But if it's working smoothly it's very convenient to use.
Good luck in your search -- there are plenty of these out there, and if you get one that's been recently overhauled it's a joy to use.