Hi David, welcome over here. I am from the Flemish side of Belgium, near Antwerp. Am also a member of the Dutch Manta Club. So as Vince wrote above the air filter brackets are an indication, but when you look under the car behind the rear axle a G/TE you will find the fuel pump:
This fuel pump with filter etc. is bolted with rubber silencers on a triangel plate, welded on the chassis rail. Remember my first Manta was a carburator one and it didn't had that. Also those older G/TE's had no Recaro's. The loom (Bedrading) of the injection goes into the interieur on the right side of the car just above the right chassis rail through the bulkhead, so this hole is about 4-5cm dia. and clean stamped. I made this hole myself on my first Manta so it was not so clean. Can be an indication... The fuel lines are made of metal but under the chassis (where the pass. seat is bolted) is a flexible part. Those metal fuel lines enter the engine bay also on the right side and from there they are also rubber lines. A 1977 model has got grey injectors, the later B2's got yellow ones.
But most important: We all like pictures so show us your car!