Hi Nicklen To answer your question, both are the same and are treated the same by bots. Don't worry, Nofollow is nofollow. Though every robot can crawl nofollow but it will not give any importance to nofollow.
Those are treated same for all robots. The difference is "external nofollow" tag will open link in new window. Same like target="_blank" attribute but doesn't give count to robots.
If you link are nofollow then crawler will not give any credit to that links no matter it is nofollow or external or internal nofollow.
No follow hyperlink not influence the link target's ranking in the search engine's index. Google consider each backlink as a vote from other webmasters to you.