Construct's Armory: 0.0.17-b
Tinkers' Construct: 2.9.1.65
Mantle: 1.3.2.24
Forge: 14.23.3.2655

Observed Behavior:
They work on other Tinker's tools (such as Crossbows, Yo-yo's, and Katanas, but you can't get additional modifiers on Construct Armor using Creative Modifiers ("No modifier found for Creative Modifier")
Expected Behavior:
You can use Creative Modifiers on Construct Armor to gain additional modifiers.
Steps to Reproduce:
1.Try to put Creative Modifiers on Construct Armor

This is a known issue, already resolved in dev environment so you'll see a fix in the next update.