Yes. Access 2003 can handle the Access 2000 format without conversion.
However, the binary (compiled) code is different between the two versions,
so you may find it useful to decompile before switching back to A2000 again.
To decompile a copy of the database, use the version you have been editing
with, and enter something like this at the command prompt while Access is
not running. It is all one line, and include the quotes:
"c:\Program Files\Microsoft office\office\msaccess.exe" /decompile
"c:\MyPath\MyDatabase.mdb"