Does the Kenwood A701A need oil?

I have resurrected my Kenwood A701A mixer and it works well but it has an overall "stiffness" about it.
On the top at the front end of the machine there is a small hole which used to have a cover and this cover is missing. Am I imagining this is the hole to take lubricating oil - if it is can I use sewing machine oil and how many drops would I use? To be honest I have put some oil into it and just hope that I have not ruined a wonderful old lady - any help would be gratefully appreciated.