My two cents
Absolutely, in fact it should!
A service blueprint is really a tool that is used to summarise what you learned from other methods in one map. So a service blueprint of the actual situation of a service definitely can’t be without other approaches.
The obvious technics that can be used before you can build a service blueprint are:
Shadowing
Service safari
Interviews
Observation
User diaries
All these technics show us how people really use a service and, therefore can help us to create a service blueprint that represents reality.