The 1975 Booster is not the same as the previous years and this company is lumping them all in the same basket
Might get the wrong part from Brake Warehouse
Try a real Opel company who sells Opel parts exclusively
$160.00 is a good price though if it is the right part remanufactured right
It is true the MC is leaking fluid into the booster replacing the inner seals should solve that problem