Oil sender

The gauge sender is usually larger. The best way is just look in the car and see if it has a gauge or a light.

How do I distinguish between the gauge and the light sender? Is there a button or a vertical spade difference between the two?

A gauge usually has more than one wire.

These do not more then one wire.

I can't tell you any more than that. You never told us what you are even trying to do and the car is just too old to have any information on. If you are trying to figure out what parts may fit, try going to www.rockauto.com and you can look up parts and look at pictures.