It could be a 76 but would have to have a serial number to verify. The machine should be in decent shape if it is 76 model. Is it close to you? go take a look and see what you can see. my cell number is 414-881-4833 if you have any questions. Sometimes I hear it and sometimes I don't, please leave a message. 

My first 330 was serial C-11541 and was shipped from the factory in Aug of 1960. This machine is a few years older than that one. Check to see if there are air controls or manual. The air controls would be in the Track steering, swing and travel selection and the swing brake.

That is a older 305. There should be nothing wrong with it but check. make sure that all the clutches operate properly and the linkages have not been moved. get some pictures of the machine and text them to me if you need any help.