As far as I am aware, all states post their well records. You should be able to search for that well by the location of the tract of land - which you should be able to locate in your county's county assessment records.
I just googled "Idaho well records" and this url was returned: https://idwr.idaho.gov/wells/find-a-well.html
If there are well records - they will tell you what the initial flow rate was on the well.
If your well was permitted to be drilled (e.g. drilled since 1987) it should have a number on it. The well may not be as old as you think because all states require disused wells be sealed with a plug and then concrete on top. To reopen a plugged well, would require getting a water well driller out to do that piece of work. It looks instead as though the well was drilled and then never completed and hooked up and just left open, which is possibly illegal depending on what was done.
Any well less than a certain depth - from memory 32' - does not need to be permitted, so your own well if it is as shallow as you suggest, may not be a permitted well, but may still be perfectly legal in your state. If you buy that piece of land and can complete a deep well - your water supply may be safer for the household than if you are using a surface water well.
If your mystery well is a correctly drilled, cased and not plugged, you should see casing - although the casing may not start until a ways down if the top of the well is in hard rock. The casing will have 'slots' cut at the level of the aquifer and the rest of the casing will be sealed to the wellbore with concrete. If the well is properly drilled and completed, the casing will be slotted at only ONE reservoir - this is to avoid cross contamination or cross pressuring between reservoirs.
if the water level is less than 175' from the surface, you may be able to get a cheap pump, or rent a pump, to do a bit of testing. Or you could book a well driller to come out an do your testing - which would provide more surety about what you are dealing with than just playing around with it. Since this is not a drought year, you may be able to get a driller reasonably quickly. That would also give you the advantage of getting a specification for everything you need to utilise that well. Installing a pump yourself is perfectly feasible if you have the skill sets and confidence, but expensive if you muck it up. (I would not attempt a pump installation myself, though I might attempt replacing a faulty pump with an identical one).
Check out this website. Their installation can be made alongside an electric pump and can run on solar or as a hand pump. I intend to get one of these installed soon. If you don't have power nearby, or just want to be totally off grid with it, you can install just the simple pump as your only installation.