$ model

$uname -a

Itanium will show ia64

systemname:/# uname -a
HP-UX sys-abc B.11.23 U ia64 3875925350 unlimited-user license

PA-RISC will not but instead show the series (9000/800)

systemname:/# uname -a
HP-UX sys-abc B.11.23 U 9000/800 139872607 unlimited-user license