In SoS I remember it being just an off-hand mention. A memory of the crash in the protagonist Decker's thoughts, which is now looked upon by society as just another historic event. In the story no one but the higher ups at Weyland-Yutani know anything about the Xenomorphs. So, Perez is never mentioned.
The character Decker is a descendant of Ripley, & I believe that is known to a certain WY representative. I'll try to read back over it after work this evening & see if anything else was mentioned in regards to Ripley by that employee. One thing I know for sure is that they are still looking for specimens even during that far future timeframe.
Also, it's worth picking them up if you can. There's evidence of an entirely new advanced alien species introduced & it's actually handled pretty well.