You're replacing an entire engine for the sake of 3 studs. Thats quite a commitment....
They are both the same mark/era so should be fine if like for like (assuming replacement is 1.2 also). You don't actually say if you're swapping all the ancillaries etc too, but if you are just changing the long block (block & head) and bolting on your original bits, then chances of any problems are diminished massively.