IMS Failure

[Porsche man]

Hi all, I expect we are all getting very tired of this subject, but I have recently purchase a 2000 Boxster S in great condition with 80k on the clock. The car has regularly been serviced and the previously owner had a new clutch installed recently by a Porsche dealer. Unfortunately the dealer did not address the IMS situation and is unable to tell me now if the IMS bearing was a single or a double.
I have read that 2000 Boxsters up to engine number 11237 have most likely have had a double IMS bearing installed.
I have also read that vehicles with double IMS bearings have only a 1 percent failure rate against those with the single bearing having a rate of approximately 8 percent
My engine number is M96 / 2167Y05233
How reliable is the information regarding the pre 11237 motors ?
It seems amazing to me that a renown company such as Porsche has no factual records of what motors have what components installed.
Hope someone can help
Cheers
Chas