Before the Internet, it would have been like looking for a needle in a haystack. I don't think I've seen a 74 X1/9 for what seems like 30 years. At least not in the northeast. On the west coast I guess they are still around.
Bumper mounts are different on the early 1974 X1/9. Location marked in red.
Doing the conversion isn't as easy as I thought it would be. From 1975 on, Fiat had to go to the impact absorbing style bumper. These used shock absorbers to mount the bumper. Well these are below the mounting points used on the 74 cars. A new mount would have to be constructed. Luckily I came across a write up on the "Xweb Discussion Forum". Listed in their "best of..." Here's a link:
http://www.network54.com/Forum/12159/message/1146706528/And+for+those+of+you+without+Jumbotrons
This will be a real help when the bumpers are ready to go on the car, After it is painted.