If your ASPD is already very high, the 1+3% won't show up, but you are indeed getting the ASPD boost. Even tho the status screen doesn't show decimal places, your actual ASPD (attacks per second) benefits from being at say 186.5 instead of just 186. The % boosts are most noticeable on low ASPD characters, and least noticeable on high ASPD ones cuz of how the % works on after-attack delay.
For example, assuming you have exactly 186 ASPD before the wings, equipping them would reduce your ASPD's delay from 14 (200-186) to 14 - (14 x .04) = 13.44, putting your true ASPD at 186.56.
This is a rough approximation, as I can't recall if equip % mods work from the 200 reduction or from the 195 reduction. If it is from 195, then it'd put you at 186.36. In either case, not enough to bump you up a whole point. It's effect diminishes the higher your ASPD already was.