No, it's the original Boing! ball, as produced by the 1986 demo (that's the date stamp of the demo code; I believe the original demo predates Commodore's acquisition of the Los Gatos Amiga, Inc., so it's probably 1-2 years older). The demo is hard coded to render the ball (it is referred to as "globe" in the code) using a specific number of latitudes and longitudes, calculating the edge coordinates of each facet. The 1986 code even takes NTSC and PAL aspect ratio correction into account. Well done, indeed
I extracted those facet coordinates and replaced the checkmark image with it, back in April 1998 (no functional changes). That variant had one limitation: it assumed a square pixel aspect ratio. It also had a few more bugs, which were not fixed until it was rewritten in 'C' for AmigaOS 4.0.
The version in the new Kickstart ROM is an updated version of the 1998 assembly language variant. The "strap" module update was needed because the copyright text had become significantly longer than it used to be, and the position and the layout of the printed text needed to be taken into account.
I also couldn't resist adding the missing, proper pixel aspect ratio scaling for NTSC displays