29.97 to 23.98 conversion

[dparsons85]

I'm looking convert 29.97 footage to 23.98 but the problem I'm having is After Effects can't determin the pulldown pattern (in Interpret Footage > Fields and Pulldown the "Guess 3:2 Pulldown" is greyed out and "Guess 24Pa Pulldown" doesn't do anything) and I'm trying to figure out why. 

Here's the issue in detail:

• I received footage from a client, fps was 23.98 and looked great. It was either shot at 23.98 natively or 29.97 and then went through a proper telecine process so there were no duplicate frames. 
• We finished the project but needed to revisit it later so I pulled the footage from the archive. When I went to reconnect the media it appared that the fps was now 29.97. I don't know if the archived footage was raw from the camera (natively 29.97) or if tech ops converted the 23.98 footage to 29.97 for archiving. I think I need to figure this out before I can determin if the reverse telecine process would work.

Can I determine the native fps? Because if it was shot at 23.98, then incorrectly converted to 29.97 I don't think the reverse telecine process would work. One thing to note, the 29.97 footage is progressive, NOT interlaced. Do cameras shoot 29.97 progressive? If not, then that's probably the issue. 

Let me know what you think.

Thanks!