No definite date or even surety as to when it was last all done. I was all over this and other sites reading up on the K100 before buying mine, so I knew what questions to ask and what to look for. IIRC, most anything maintenance and tuneup was done by PO. Splines, filters, plugs, etc.
I have a spare FPR, so might as well try. Gotta dig down to it to check the vacuum lines anyways. Air filter is good. Was gonna replace all the vacuum lines last night, but got sidetracked making a new key pin post for the makeshift lid of the alternate relay box, AKA lower half of stock airbox. After new vacuum lines are in, I'll try an adjustment. Weird how it could just fall out of adjustment suddenly.
Oh, and I just found a vacuum test kit on sale at the local Harbor Freight, so I'll try the TB sync as well, after the vacuum lines are all set