From page 132 of the user manual for the Samsung Gusto 2:
Phone Info View software and hardware information for your phone, your assigned telephone number, an icon glossary, and manage software updates.
1. From the Home screen, press the Left Soft Key Menu ➔ Settings ➔ Phone Info.
2. Use the Directional Key to highlight My Number, then press OK to display the Mobile Device and Identification numbers.
3. Use the Directional Key to highlight SW / HW Version, then press OK to view the phone’s software version, PRL, ERI, Browser, Media Center, MSUI, Hardware version, ESN, MEID, and WDC, and Software Update Client.