Thanks to a useful post on Yahoo! Answers, I realized there's actually three sets of Thieves Guild Armor you can spawn through the console, and the UESP is listing the wrong one. The ones you want are as follow:
player.additem 000d3ac2 1
player.additem 000d3ac3 1
player.additem 000d3ac4 1
player.additem 000d3ac5 1
I've just confirmed it working.
The ones the UESP list aren't visible in inventory view (they do show up in the world, though). I suspect they're meant for NPCs, since many NPCs carry invisible-from-inventory armor. Being different armor, it won't work with Tonilia's quest.
For completeness's sake:
00036584 - Armor, NPC version
000d3ac3 - Armor, Basic version
000d3acc - Armor, Upgraded version
00036583 - Boots, NPC
000d3ac2 - Boots, Basic
000d3acb - Boots, Upgraded
00042be9 - Glove, NPC
000d3ac4 - Glove, Basic
000d3acd - Glove, Upgraded
00036585 - Hood, NPC
000d3ac5 - Hood, Basic
000d3ace - Hood, Upgraded
additemwill not have any negative side effects, unless you add something stupid like a quest item. – kotekzot Dec 3 '12 at 7:27