Either is fine. We had some last minute cancellations to DD's party. Two of them ended up getting the gift to us and the third said she would, but never did. I, of course, am fine with it.
Honestly, the gifts brought outside the party made me feel weird because I was less interested in the gifts than with just celebrating my daughters birthday. So, I dunno... I never would have cared if I never saw any gifts from people who had to cancel (or otherwise).
SAHM to Magnolia May (09/10), Luke Russett (04/13) and expecting 11/16. Wife and best friend to my airman.