Usually, if the IMS has been replaced, it is one of the top selling points. If it is an L&N bearing, there will be a reg sticker somewhere on the car. Zero documentation = assume not. At 116k miles on the car, it is reasonable to think the clutch assembly has probably been replaced. You can X/O the bearing with the engine in the car. You will need to pull the trans for access.
Have you changed the oil and inspected the filter? Consider pulling the pan.
Lots of IMS info/videos on the interwebs.
https://www.pelicanparts.com/techarticles/Boxster_Tech/14-ENGINE-Intermediate_Shaft_Bearing/14-ENGINE-Intermediate_Shaft_Bearing.htm
1997 Porsche Boxster
2018 Porsche Macan
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