I've gotten a surprising amount of mail about this, so here's the answer:
/etc/Login and /etc/login don't write to a certain file in /adm, which
finger looks in. (/adm/something/lastlog?)
I've been told that the fix will likely (but not certainly) be in 2.0.1.
---
Alexis Rosen
Owner/Sysadmin, PANIX Public Access Unix, NY
{cmcl2,apple}!panix!alexis