YourConfused, I could not find another fitting anywhere in town after searching auto parts stores, radiator shops, looked at 20 or more blown rads at one place and none of them had the same fitting as my chinese special.
You can not replace the hex nut because the copper tube is flarred. As far as using the soldered one, my mechanic said the tube was not straight when he did the quick solder job, and thinks it would leak behind the nut. Anyway Thanks to OTom, I will have it tomorrow and put it in. Thanks for your input.