Yes, in that context, it means "available" or "that you you're not using".
Have you got any sugar going spare? I want to make a cake and I've run out.
He asked me if I had fifty quid going spare. Hah! Not this close to payday, I don't. (quid = pounds sterling (UK currency))
Has anyone got any printer paper going spare? I've only got one sheet left and I need to print ten posters.
Note that in BrE, it also has another meaning - "to be frantic/panicking" or "to be very angry".
I'm going on holiday tomorrow and I can't find my passport. I'm going spare! What if I don't find it?
When she told her boyfriend she was moving to Spain, he went absolutely spare. He never thought she'd actually go without him.