Biometric notices (Appearance necessary / not necessary)

[Josephin&Robert 4]

Hi, 

I am in the I-751 process and I received two letters in the mail. 

 

First says biometrics are not necessary because they use my old ones.

Second one gives me a date, time and location where to go for biometrics (letter is dated two days after first one).

 

Case status says "fingerprints are taken" and they "have been applied to my case".

 

I called USCIS and I think they also weren't sure and said to go to the appointment and then we will see. 

 

Has this happened to anyone? What does it mean?

I will definitely go to the app. to be on the save side but I was wondering if anybody knows something.

 

THANKS a lot!