Yes, because on emulsion style, the seal is on the bottom of the shock cap to below the threads on the body. With bladder style, the bladder seals the top of the shock cap to the top of the body. This is important because you drill a bleeder hole into the side of the threads for bladder style. If the same cap is used for emulsion, it no longer has a secure rubber seal from letting air into the shock. The hole in the side of the cap just has a couple of threads above it.