Normally, yes as long as the libraries are VST2 and not VST3 which Finale does not support.

Here is a Knowledge Base article on the subject.

https://makemusic.zendesk.com/hc/en-us/articles/15924720990743-Using-Spitfire-Libraries-in-Finale

Paul two things. Have you thought about upgrading to 27? I would and I would also try NotePerformer 4 before you get too far involved with Spitfire sounds. NP4 may do all you want and it is pretty friendly with Finale. Beside being way cheaper! Just a thought.