convert fails to produce gif87a format

[djd]

OS: Windows XP

Version: ImageMagick 6.5.8-3 2009-11-28 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2009 ImageMagick Studio LLC
Features: OpenMP

convert -size 200x200 xc:white gif89.gif

convert -list format
....
GIF* GIF rw+ CompuServe graphics interchange format
GIF87* GIF rw- CompuServe graphics interchange format (version 87a)
....

convert gif89.gif -format GIF87 gif87.gif

# giffer extracts parameters from a gif file including the 6 byte identifier.

giffer gif89.gif
Header=GIF89a
....

giffer gif87.gif
Header=GIF89a
....

Thus, unless I have misused it, the GIF87 option appears to have failed.
Can it be fixed?

[magick]

To generate a GIF87 image, use this command:

• convert gif89.gif gif87:gif87.gif

[anthony]

See IM Examples, Common Formats, GIF,Related GIF Output formats
http://www.imagemagick.org/Usage/formats/#gif87