pretty much yeah, it wont stop em leaking fuel trhough, but if just an airleak that';ll be sorted. can check inj function while they're out easily enough. pull all 4 out and pop each into a container of equal size. take out the fuel pump relay and bridge the 2 largest terminals, then manually lift the flap in the airbox as high as it will go, then release it. the injectors should spray a nice even cone of fuel. pull the bridge wire off the relay socket, then wipe the tips. they shouldnt drip for around 5 minutes. then check the volume delivered is the same on all 4.
if any injector sprays less or a poor pattern, swap that injector to another pipe and repeat the test. if problem moves its injector, if not its the fuel pipe or metering head. Before you undo the injector pipe wait till pressure has gone down, this will take several hours. or just be extra carefull with rag held over if you liek to live your life dangerously!
if one of your injectors is faulty just replace all 4 as a set, gsf do bosch ones and sometimes you can buy brass mercedes injectors from ebay for a bit cheaper. or watch the classifieds, someone was selling a set a while ago on cgti.