i took the plunge and tightened the strings and...
...it doesn't hold tune, but it's a 50 year old guitar that i suspect has barely been played at all, and appears to have been restringed with old strings.
i'm going to get some nylon strings for it tomorrow,
i actually think it's fine - it's just old and has barely been played. it should stay in tune when i play it more....
...but i'm concerned about the bridge being weak, so we're going to turn it into a classical guitar, first.