zone syntax question

[CT]

old zone file
---------------
$ORIGIN .
$TTL 3600
example.com         IN SOA  ns.example.com. root.example.com (
                                 2010071402 ; serial
                                 10800      ; refresh (3 hours)
                                 3600       ; retry (1 hour)
                                 345600     ; expire (4 days)
                                 86400      ; minimum (1 day)
                                 )
                         NS      example.com.

$ORIGIN example.com.
                 A       192.168.1.1
                 MX      10 ns.example.com.
www             CNAME    example.com.
---------------------

proposed new file
---------------------
$TTL 3600
example.com.        IN SOA  ns.example.com.root.example.com (
                 2010071403      ;serial
                 3h              ;refresh
                 1h              ;retry
                 1w              ;expire
                 1h              ;ncache
                 )
         IN      NS      ns.example.com.
         IN      MX 10   ns.example.com.

;localhost       IN      A       127.0.0.1
                 IN      A       192.168.1.1
www             CNAME    example.com.


My question...
Will my proposed set up work on the "old bind" version..
and it is syntactically correct ??

Thx
Charles