Original IIgs ROM upgrade?

[John Le Febvre <john@klatch.demon.co.uk>]

I am posting this for a friend, so forgive any mistakes as I know 
practically nil about the IIgs.

A friend has an original IIgs which he thinks is a ROM 0.  He seems to 
think that this can only be upgraded to a ROM 01, and that he would 
need a ROM 02 to upgrade to a ROM 03.

Can someone tell me if this is true, and if not, what he could possibly
upgrade to?  I think he is still running pre GS/OS software.

I have volunteered to download the latest GS/OS System 6.0.1 for him,
as long as he can use it on his machine.

Thanks in advance
-- 
John