I recently purchased my first Corvette and it is a 1991 C4 convertible.  I am a little confused about what I actually have.  I have confirmed that the numbers all match and ordered the build sheet and window sticker from the Corvette Museum.  The VIN number and the build sheet all call for a L98 engine but there is a plaque inside the drivers door that says it is an LT1 (picture attached).  I purchased the car from a private owner who claims this car was built for a retiring GM executive.  I have found no documentation to confirm that.
Any suggestions as to how I might find more information on this car?
Thank you

That plaque is an aftermarket item that is readily available in multiple configurations. Anyone could have stuck it on without knowing what the configuration really is.