If its made out of metal again it won't have one.
Wrong, we've recently bought an EV97 SL Eurostar which is an all aluminium microlight and is fitted with a BRS. It's covered by a metal panel inset just behind the engine, in front of the canopy and features open drilled holes with small tabs so the panel will easily pop out on deployment. It also has the red warning triangle as mentioned previously. Our C42Bs have got BRS too. Very smart system!