Given what Vince has said it would be a bad mistake to remove it, it is different, unique and useful.
Loads of pictures of field/workshop modifications carried out in service have been posted on here in various threads, and the chances of this being one of them seem quite high to me. Just because no documentary evidence has turned up yet, does not mean there is none.
It would be a pity to remove it only to then discover proof that it was actually much more interesting than even those posting to this thread have found it.
As the owner of an MV that doesn't conform to the usual spec, your conversations at shows and such will be much more interesting, like when the chap who drove or built it turns up one day!