Not in the strictest sense, no. Jebra's visions can mean anything, they can tell the character of a person, or what they're planning to do (E.G. she foresaw Cyrilla dreaming of hanging herself) or she can see visions of what is to come.
They can be quite straightforward, or they can also be even more obscure than prophecy is.
Also, prophecy is given by a Prophet. Jebra is a seer, she does not have the gift.
-I think further clarification is in order. It can all be summed up in the fact that Jebra is not a Prophet and therefore does not give prophecy, but it is much more complex than that.
A Prophet is a wizard whose gift has that inclination, but a Seer, as might be implied from the word, is one who sees. The visions Jebra has are indicative as to the state of flux a person's thoughts and well-being are in, and they do not tend to indicate long-term events. For example, she saw Zedd with wings, flying high above, and being dropped into a ball of fire, shortly before Gratch came to them and took Zedd to Aydindril, and Zedd was subsequently captured by Ann and participated in the destruction of the Palace of the Prophets. A seer's visions, therefore, don't seem to be capable of predicting events that will take place in the distant future, and only seem to be connected to the life of the person whom she sees a vision of.
On the other hand, prophecy can predict events thousands of years in the future, as most of the prophecies regarding Richard were very, very old (probably over three thousand years old). They also tend to be concerned with the well-being of nations, magic, and the world itself.
As stated, Jebra does not have the gift in the sense that wizards and sorceresses do, but I think we can infer that her Han is more advanced than that of a normal, ungifted person. She has visions, obviously, and she can observe people's auras, which would indicate that she does have some form of magic, at least. The only other person we see directly deal with auras is Drefan Rahl, and he had a lifetime of practice in using them in the healing process, but was otherwise ungifted, though not pristinely, like Jennsen and Oba.
I think that we can further assume from this that a seer can be naturally inclined to have her abilities, or can have the "calling", much like wizards do, and learn to see auras and intrepret their appearance. In this sense, it might be possible for a seer, who already has a somewhat more powerful Han, to learn to become a sorceress, though she would never be as powerful as one who was born a sorceress. Again, this is all just guesswork.