new pc, new donation necessary to get a second G-key?

I just build a new PC.
I will still be using my laptop that has the G key for when I play during travel, so I stioll need to "keep" my old key.
I would like an EXTRA key for my new and powerful machine, do I need to make a new donation for that key or can I get a second one as I already donated in the past?

Thanks for the answers and help!