Build data from mg-rover.info is as follows:
ZT 260SE 384
ZT 260 180
ZTT 260SE 114
ZTT 260 37
so it does look like non SE's are the rarer model by some margin. The same site shows that my ZTT is the only non SE 260 in trophy blue, so I am now feeling rather exclusive even if rear passengers need some exercise on the window winder to get some fresh air in the back. (Still have electric windows in front so I am alright ).
When I bought mine a few years ago condition, documented service history and mileage were the higher priorities over spec, although at the time I did not appreciate how few basic spec ZTT 260's there were.
Mike