Not quite - the Zeiss 4.5/21 is definitely smaller than the 2.8/25. Size, from the manufacturers' specs:
Zeiss 4.5/21: diameter 53mm, length 34mm
Zeiss 2.8/25: diameter 53mm, length 49mm
CV 4/21: diameter 49.6mm, length 24mm (28.5 w/hood)
Hope this helps, even if I haven't a pic side by side for both lenses. 😀