The last WD speedo i pulled apart disintegrated into bits because the main body was made out of melted down pots and pans! So watch out, i would rather buy a later or earlier version and just replace the face.The speedo i speak of was in excellent visual condition. I used the mechanism and transferred it onto another body.
When I first saw those items, I wondered if a bike was really worth more in bits. It looks as if I was wrong.
The plus side to breaking bikes is that it might help five or six better ones re-appear but the scary part is that theft for dismantling must be a real risk again.
I didn't exactly build my Norton from parts but it needed a lot. It was just possible five or six years ago but I agree that it no longer is.