Yes. While editing your project, you can click on the Pricing Calculator to change the price and options.
Note that if you turn off the option for Hardcover, you will not be able to turn off the option for Softcover, or vice versa. The eyearbook option can be turned off at any time, however, as long as none of the Sections are Locked. If a section is locked, you can unlock it, change the eYearbook option, and then relock the section(s).
Note: Enabling/disabling the eYearbook option can only be performed prior to any sales. Once a pre-order has been placed, the eYearbook option can no longer be changed.