Chris
I agree with Dan that your green tower may have been modified. I have two myself which are “D” cell powered. They don’t light very well with a 1.5 V bulbs. The common is reliant on the contact from the globe to swivel contact, which isn’t very consistent. Easily bend over the one tab so you can swing the base off, if its battery you will see the spring coil at the top of the square base. Here are some pics to help you.