Old refrigerator risks
Safe?  Yes.  Economically wise?  No.
Refrigerators older than let's say the mid to late 90s are woefully inefficient, and use quite a lot of electricity compared to ones made in the last 15 years or so.  Buying a newer fridge (even one 10 years old) will often pay for itself in just a few years in the amount of electricity saved.
So if you're planning on using the fridge for more than a few years, it's likely wise to not run it and find something newer.  Utilities in the US (and possibly even other countries) will often even give you a rebate on disposing of an old fridge like this.