SS1 binaries on Sun 4?

[david at ics.com]

Under what conditions will stand-alone binaries built on a SPARCstation 1
running 4.0.3c not run on a generic Sun4 running 4.0.x?  What would be
best would be an answer of "oh, no, they'll always work", but I suspect
that universal compatibility doesn't exist here, but I don't understand
what conflicts might arise.

Replies by email would be best; thanks in advance.