In this episode, Barney and Ted talk about old Guns n Roses vs the new Guns n Roses. The title is a word play on the Guns 'n Roses album "Appetite for Destruction"
When Zoey reads out the second sign it says ' it's always 4:20 somewhere' this is a direct reference to April the 20th (International counterculture holiday, where people gather to celebrate and consume cannabis).
In this episode Barney is trying to convince Ted that "New is always better" when Ted asks what their oldest scotch is she says Glen McKenna 30 year old. In Season 4 Episode 4 "Intervention" The gang wants to celebrate with their "Most Expensive Scotch" to which Wendy the waitress says it's "Glen McKenna 50 year old and it's $2,500"