I would, and did. Our shower was co-ed. No one actually purchased any of it, I think we did the boppy cover we wanted (we received a hand-me-down boppy with a "boy" cover so I registered for a girly one) but I'm not sure if that counts...
It isn't a big deal though, someone may get you a pump if you're asking for one but if not then you can get it yourself with the completion discount coupon you will get for your registry. Most other nursing supplies like creams/pads/shields/etc. are $5, $10, $15... so they're easy to run to the store and pick up.