I have a feeling that if there was any genuine weight to that theory then that wouldn't be the case. As it appears, the theory has only hung around as long as it has due to an uncorroborated posting on a US pilot board with absolutely nothing backing it up.
For random background, it was David King who oversaw putting the Lockerbie 747 back together and proved exactly where the bomb was placed, so it's not like he's unknown in the US, nor is he politically tied, having been the head honcho at the AAIB since long before the current administration (to use US terminology) was in charge. From what I've read the NTSB hold him in *extremely* high esteem.