I don't intend to pour cold water over this, but a realistic price tag is around the £300 figure, based upon three similar (but newer) ones sold this year alone. Re the age, yours do have a much earlier serial number which you should easily be able to date. But that won't necessarily add to the value, the value is largely dependent upon the state of the lenses, which look good, only a little dusty. But be careful when attempting to clean them that you don't scratch them.