I know that restoration could be a lot of fun
BUT
I frankly see a lot of needs in such an old machines,
apart pump, flowmeters, solenoids, etc etc
the concern with Rancilio old machine is having access to control boxes,
there are repairs possible to then (James is one of them)
but as usual when it comes to this $$$$$ investments
make sure you know all of it before going to deep,
make 100 % sure for example that the boiler is solid and there are no pin holes which will be a main issue.