Thats about what I thought too. Upside down bolters? Apparently so for the Space Wolf Slayers Upgrade Pack #2. Don't fret if yours is like the picture above, replacements are being worked on.
via Wildweasel on B&C
http://www.bolterandchainsword.com/topic/344258-fw-sw-grey-slayer-upgrade-pack-2-being-redone/
