If you have a 1200 ute & it came from the factory with a two piece driveshaft, then it's a longbed.

If it's a single drivshaft, then it's a shortbed.

Pick up the yellow pages & ring some driveshaft shops. They should be able to tell you if they can convert non serviceable Datsun driveshafts to serviceable types.
I have a later B310 shaft that was converted using Holden uni joints I believe.

This will be a whole lot more cost effective than buying a new shaft.

I think it is a short bed. But Im not sure. I have nothing else to compare it with. lol. It has an a15 and dogleg 5speed conversion if this changes anything. But it is a sportstar.

You have longbed SportStar?

The centre and rear u-joints in my drive shaft are on the way out. They are pretty bony at the moment and dont look like they will take much more. Just looking at them they seem to be the non replaceable type. Is there a way around this or am I looking at a new drive shaft????