Correct. We've been seeing a bunch of confusion about this, so let me try to clarify as best as I can:
The opening of Blackrock Foundry is completely independent of the release of Patch 6.1. At roughly 10AM Pacific time tomorrow, the entrance to Blackrock Foundry will activate, and you'll be able to zone in and start killing stuff. No patch necessary.
Similarly, any of the new changes or features listed in the Patch 6.1 PTR notes
will not be live until Patch 6.1 actually releases. That includes the Heirlooms collection, stage 4 crafted gear, new follower missions, various talent buffs, and the updated Blood Elf model. Any changes made prior to the release of Patch 6.1 (including balance changes and bugfixes) will be noted in our Patch 6.0.3 Hotfix Blog