Probably. But there are always risks opening e-mails from an unknown sender or even e-mails from known senders if the subject is apparently faked like “I found this site you should like”. It doesn’t matter if it’s in a Spam folder or not. Valid e-mails can be incorrectly identified as possible spam. E-mails are usually sent to the Spam folder to give you a chance at retrieving ones that are valid. — Tom
Be very careful. Many security incidents start with a user clicking on a link included in an e-mail message. If you don’t know the sender it is probably a good idea not to open it, and if you know the sender but are unsure if the message is legit, it could be a good idea to contact him/her to ask about the message.