Don't worry too much about not having multicolored lights. My first flasher was a Super Sixty I bought for open water and then converted for ice use. Spend some time in areas you are familiar with and adjust the Sensitivity and Gain until you are used to interpreting the signals. While modern units are more advanced, this won't be a horrible start provided the price was right. The biggest downside is the lack of definition in shallower water (<5-6 feet).
Good Luck....
/mike