Jo Ann,
I think my 57 Sovereign of the Road has the same window style as your 57
Bubble. If so, that style was changed in 58 or 59. So the 62 gaskets would
not fit. My 59 Ambassador has windows which require the gasket offered by
AirstreamDreams. The earlier gasket is available however I don't have the
contact information. There is a guy who advertises quite frequently on the
VAC classifieds located in California that offers this gasket at about
$1/ft. Its a private person not InlandRV. This style of window was only used
for several years from 57 or so back. If you check out the archive section
of www.vintageairstream.com you will see the differences in window styles
and hopefully pinpoint exactly what your looking for.
Good luck with it.
Colin