Open up OpenIV and open up your latest update.rpf (1737).
Open up a new instance of OpenIV and open your previous unmodded update.rpf (1604).
Compare all file sizes.
If that is too much work, I can only say that you should have kept a record of some sort when modding your rpf. Every mod I download and install, I update their readme.txt with any info I changed along the way. I also move mods I used to a separate folder from the mods I downloaded but did not use (e.g. path\to\downloaded\mods\unused VS. path\to\downloaded\mods\used). It helps me keep track of which mods I have currently installed and which ones I do not. All readmes contain which files went were and what changes if any.
My only suggestion, so far. Maybe someone else knows a better way.