True, and the writer of Hebrews seems to imply that Melchizedek was an appearance of Christ Himself.
One of the things he said was that if one plots out the lifespans given in the account, one finds that Shem could have survived into Abraham's lifespan.
Imagine :)
(oh, he also said his belief was that Melchizedek was a "type" of Christ, but that the preincarnate Christ Himself appeared only for brief periods and to certain people; not long enough to be known as King of Anything, or have an earthly kingdom. Interesting...)