NOS Speedo Parts: Smiths? Stewart Warner?

[nycet3]

I have this lot of old speedo parts in my collection. Received all of it from the same person. (He inherited a bunch of old bike stock.)

One gear is Stewart Warner. As for the rest, I can't be certain. One angle drive is used. One is NOS. A serial number is visible. Also there appears to be a stamp. Not certain if it's a maker's mark.
One of the spoke-mounted gears is used. The rest are NOS. they're stamped 28 and 30 respectively.

I've searched high and low. The closest example I could find was a Smiths.
Here mine:

Here's my Stewart Warner gear:

And here's the Smiths example taken from the Internet:

Oh, and included with the speedo parts were about 100 NOS oil filler hole plug clips:

Anyone have any ideas? Breaking my brain. Thanks. Joe

 

[nycet3]

For anyone wondering, the parts posted above are in fact Smiths speedo parts with the exception of the Stewart Warner drive gear.

I believe the parts date from 1950s. Not certain.