TC1

We are moving a 401(k) from another provider to our platform. The plan has both related and regular rollover. We set up 2 separate money types to keep the funds separate. I'm being told that I need to find out the prior sources that the related rollover came from, like deferral, match, etc. I have never heard anything like this before. Is this correct? At prior employers, we never got this information, and I wouldn't know what to do with it if I had it. Thanks.