You would be much better off money wise if you bought a used pull trigger and kept your release trigger (or sold it as a release trigger). It will cost less to buy another whole used trigger group.
And definitely they changed over the years so the lengths and sizes of the trigger, hammer, etc. are different and are not interchangable in many cases. I have had 5 Ljutics and a couple of extra triggers at different times and have noticed numerous differences. Sometimes it is a few thousands of an inch in the part of the trigger that fits into the hammer but that makes the parts not work together, but the entire trigger group normally interchanges. Some of the older trigger groups were a little narrower (they fit in a newer model but won't fit the older model without a little work). Also the release button hole is different sizes (the larger hole works fine with the smaller button but not the other way around without a little work).
Basically try another trigger group and see if it fits and buy it.