The best answer to your question is "maybe." In most cases, yes, you can probably get away with "blindly" upgrading /patches for a release.
However, there are occasionally new things added in /patches -- for example, 11.0/patches/ had a new mozilla-nss package added for gaim's SSL suppport to work properly and reliably. Lots of people upgraded the gaim package, but failed to add the new mozilla-nss, so the GTalk and Jabber protocols didn't work anymore. Then they went to #pidgin, and the Pidgin devs concluded that the Slackware package was broken, when in reality it was the user who was broken.