ER replcheck and erkey columns

Hi all! I'm working with Solaris 10 on Intel. v 11.70.xC4. I'm still working on getting my head around the replication check process. We have a source server that is going to be migrated to new hardware. Hp-ux to Solaris. I'm going to user the new Solaris server as the sync server. If we test the sync process from our test environment ( with actual production data ) to our Solaris environment and then flip from our test environment over to our production HP-UX and start syncing again, all the same values that were updating during our tests, are still applicable, right? And also, which columns are getting "checked". Just "ifx_replcheck"? That is the checksum info on the row, right? I guess I'm confused, because I expected both sides to get hit just as hard by updates on ifx_replcheck, but it seems like only the sync server is getting updated while the "old" server is simply getting parsed. Is the only thing getting updated the ifx_replcheck column on my sync server? Is there any good links out there explaining this process?