Rock Band 3 allows for 1--7 players, either locally or through online game services, to use various instrument controllers to accurately simulate the playing of music. In addition to supporting the four Basic instrument controllers from previous Rock Band games (lead guitar, bass guitar, drums and vocals), Rock Band 3 adds support for two additional microphones for singers to provide backup vocal harmonies (previously found in The Beatles: Rock Band and Green Day: Rock Band), an electric keyboard as a new instrument (or any MIDI-compatible keyboard), plus support for a specially made 102-button MIDI bass, and an actual Squier guitar by Fender. Support for MIDI compatible electronic drum kits as well.

Can we conclude that can you use rock band 1 instruments rock band 3?
yes