I have understood that the only game in town are the 70-73 repops;
I believe Rocky's book shows the real 1974 & 1975 tips.
If my memory serves me (because I was schooled in this not too long ago), the 1974 tips were essentially the same as 1970-73 except they were 3" longer (the angle cut was a running change, the parts were
supposed to be the same).
HERE I found the thread where I was taught more about the tips - and in that thread is a quote from Rocky showing the correct parts.