Hi! I'm repairing my bike from 70s. I'm not sure has someone replaced the cassette or wheel. I tried to remove the cassette, which is 5-speed Shimano, Uniglide (UG) I think. Has Shimano made 5-s cassettes on 70s? I firstly thought that it could be removed with two chain whips. But now I think it is freewheel and I need freewheel remover, am I right?

The cassette has these markings: Shimano UG (or can it be VG?) CG.

Pictures:
http://i.imgur.com/roQuit4.jpg
http://i.imgur.com/TREVdLu.jpg
http://i.imgur.com/ONMhiM9.jpg