well, the man page says:
\$ if the effective UID is 0, a #, otherwise a $
so I su and do echo $EUID and I get 0
which means, as I understand, that the $ should turn into a #. why does the symlink change anything? it's just a pointer to a .bashrc file to run.
note the PS1 line is in double quotes (so it shouldn't be a literal $):