Was there any previous history in Hindu practices of exchanging rings during marriages?

Answer : There is no such practice in the sanathana dharma system. However, the presenting of ring for the newly weds were in practice even in those vedic era which can be safely assumed from the Purana and Ithihas. But this practice was not as a wedding or betrothel rituals but considered as a wedding gift only. The most sacred thing of the wedding is Mangalya Dharanam, Agni, Arundhathi and can be judged as concluded only after Sapthapathi.