Yes, restore's always been able to restore dumps from other-endian machines. 
It just checks the endianness of FS_MAGIC on the tape and starts swabbing
things if needed.  If I remember right, it has provisions to swap both bytes
and quads, though I don't remember how it detects that it needs to swap one
and not the other.

It's kind of a shame that restore's not universal anymore.  It used to be,
despite all the gross contortions gone through to ensure this, and in fact the
easiest way to read an incompatible "4.3" filesystem used to usually be to
hack on dump to make a dump-format archive of it (usually trivial) and then
feed it to restore.  

Restore should really get fixed to deal with both types of filesystems.  The
easy way to make a version of restore that'll handle old dump tapes is to
build it against the old includes, but in theory this should never be
necessary.  Previous filesystem changes that would have introduced
incompatibilities always included corresponding tests in restore.  (Though, of
course, they should probably have been in dump instead...)

If I have the time, I'll try to mangle together a fix for this myself.  This
is a large icky mess.

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