I think there are a lot of rumours about bufotenine degrading, but I think they are just that: rumours. Archeological evidence of snuff use in south america has shown bufotenine to be present intact in material that was over 1000 years old (Torres, C. M. et al, 1991). So I would say you're safe to go
The only possible degradation product I can imagine it to form is bufotenine n-oxide, which is probably just as active (Trout's notes), and anyways can be re-converted back to bufotenine with simple reduction process of zinc and acetic acid.