It depends on your definition of spam. It is unsolicited email, so if you think all unsolicited email is spam, then it is. However, if you kindly explain that you do not intend to bother them with follow ups that this is a one -time email only and that you got their email from , well, where else their site, I think you should be okay.
Now, if their email was not listed on a site and lets forget for a second the fact that whois records are public info, they may be more sensitive if you (went out of your way) to look them up.
Have you tried one of those anonymous domain name offer services for this type of ice breaking?