Ok, I've compared the rpm and tgz binaries mentioned above and their contents are the same build.
My request is that you please align the base names.
i.e. one shouldn't have i686 in the base name and the other i386 when the contents of the rpm and tgz are the same.
I used rpm2cpio to extract the contents from the rpm to compare against the tar file.
example: rpm2cpio splunkforwarder-6.1.4-233537.i386.rpm | cpio -idmv
I then used beyond compare www.scootersoftware.com to run the comparison of the tgz vs the rpm.