Trivia: Elvis Presley did indeed play Binghamton, NY War Memorial Arena the week Star Wars opened (25 May, 1977) as Wes describes. Elvis played Binghampton on the 26th and 27th of that month (wearing the white jumpsuit.) That makes Wes--3 years old in 1977--28 years old.
Elvis Presley was born in 1935 - Jesse Garin (and Michael Philip, the actor who plays him) doesn't look 67 years old here, but he kind of would have to if he were really Elvis' twin brother.
Although King Master Lobo's fangs look fine, some of his minions have vampire teeth where the two incisors are very close together: either the front two upper teeth, or the two teeth to either side of them. The incisors are typically the third teeth to the left or right on the front.
Grace: Any minute now a gang of Elvis-impersonator vampires is gonna strike out and turn every last mortal Elvis fan in this hotel into a blood-sucking freak.
Donald: I was afraid of that.
Grace: You were?
(seeing Wes in a gold lamee Elvis suit)
Grace: Why are you dressed like Little Richard?
Wes: Shut up!
Tucker: Did you find the vampire?
Grace: Are you kidding? It's like trying to find a needle in a stack of needles!
Grace: How many times do I have to tell you I didn't know he was a vampire until our second-to-last date?
Wes: Even though the King never did a sci-fi flick, we gotta help him.
Wes: So you're a vampire slayer?
Jesse: Teenage girls and sci-fi geeks say "slayer". I'm a vampire hunter.
Many little in-joke references slipped in to various famous lines and movies that Elvis Presley did.