The first Shelby is an alarm clock with an ivory or brown Bakelite® case. The style 2 Shelby has a round metal case with plastic pearlescent dial and a cast base. Style 3 has a regular dial and a stamped metal base.
When identifying a Shelby style, observe the case shape and ignore the case and dial color, because the styles were made in various case and dial colors, as shown in the detail page for each style.