[Lynn Eades]

No Ben, its not a Brit / Canadian thing The British rubber rests are a higher profile than the Canadian ones. I'm not saying wood was not used. It may have been a rubber shortage thing. The steel tube on the MkII was an obvious answer.
For someone doing a restoration, I would suggest the wood as a good option. easy to do, durable and looks the part. A bit of polished Jarrah would be great!
I have posted on the differences, but can do photos if someone wants them.

Rich, I do have a used rubber step insert. Until you just mentioned it, I never knew anything about a "checker plate" (grip tread) metal step insert.
We are all learners.