If the bow has some "backcurve" without tension it's quite likely, if it's otherwise of fair quality, that even a local repair shop with reasonable experience might be able to "reset" the curve to a more normal condition, if it is in fact a bit "bent."

If, as I think you implied, you're not an experienced fiddler, it may be difficult for you to judge what's the "right" tension. Modern bows are intended to "straighten under tension" up to a pount, but what is perhaps the "defining feature" is that once an appropriate initial tension is applied the tip can rotate some by bending at the more flexible tip of the bow to maintain quite uniform hair tension as you vary the pressure against the strings and the deflection under pressure of the bow hairs.

Some fiddlers, especially "folkish" ones perhaps, like a rather high bow tension to make it easier to "bounce the bow" around on the strings. Those who use a more classical(?) technique will generally, I think, use somewhat less tense hairs, although there's considerable variation in "personal preference" among players, and even a fairly skilled player may want some change in tension when playing a particular style of music.

Advice from an experienced player or luthier/bow maker who can actually examine your instrument - bow and fiddle - would still be recommended before you become too firmly attached to your own conclusions as to what you have.

John