I have a paper wallet that I made from moneroaddress and wanted to import it to the GUI. Can I import it by starting up the GUI and clicking, "restore wallet from 25 word mnemonic seed," and entering the seed from the paper wallet?
You are correct, that's all you have to do. However, when you restore it in a GUI/any live method its not a cold wallet anymore. So be very extra careful that the computer you are working has an anti-virus and you are positively sure that it is clean from malwares/keyloggers.
If you want to make your paper wallet still "cold", there are other ways you can view your funds. E.g. How can we view the balance of a cold wallet storage and keep it cold?