Yes, those are trusted sources for ThomasV's key. The easiest way to save the key is by copying the text from that first link, and pasting it into your favorite text editor. You can then save it on your system with the name that you choose. The name of the file isn't important, but remember where you saved it so that you can browse back to that location while importing into your GPG app.
Besides the method provided by DireWolfM14 you can also highlight the link from ThomasV's key and press "CTRL" + Mouse click which should prompt the right click menu on Safari. Then just select the option "
Save Link as..." and you'll be able to save directly the file/key (.asc) into a directory of your choosing.