Yes you can put it together without the clip so long as you locate it and hold it as you put the slave on but your rod is too far in so there is a problem.
Here's a piccy of a typical fork. The dimple in the centre is where the fork itself pivots....if this gets worn enough and wears through there's nothing you can do but remove the gearbox and replace the fork.
The dimple on the right is where the slave cylinder rod sits, if it wears through there it is possible to weld a dished washer to the end of the rod as an emergancy measure.....you should be able to see the right side of the fork with a torch through the slave hole