Well, if you're not trying to match the original, you might find something here: https://www.mcmaster.com/products/bumpers/system-of-measurement~metric/

Also, look at the results of this google search: https://www.google.com/search?q=metric+stopper+bolt+with+bumper&sca_esv=63ec7e79828cdf8c&biw=1920&bih=911&sxsrf=APpeQnsq13L7bEDRQtXSUDrClx_F-hUqCw%3A1783112014069&ei=TiFIasLjA-D-p84PhOSlEQ&ved=0ahUKEwjCwsXxsbeVAxVg_8kDHQRyKQIQ4dUDCBA&uact=5&oq=metric+stopper+bolt+with+bumper&gs_lp=Egxnd3Mtd2l6LXNlcnAiH21ldHJpYyBzdG9wcGVyIGJvbHQgd2l0aCBidW1wZXIyBRAAGO8FMggQABiABBiiBDIFEAAY7wUyBRAAGO8FSPsZUM4PWLsXcAF4AZABAJgBrgGgAbkGqgEDMi41uAEDyAEA-AEBmAIIoALJBsICChAAGEcY1gQYsAPCAgcQABiABBgNmAMAiAYBkAYCkgcDMS43oAfQE7IHAzAuN7gHxwbCBwMyLjbIBwqACAE&sclient=gws-wiz-serp

20 hours ago, Warty said:

car #1286. Provides a data point on the style used to that point.

That style (without the Phillips feature) was used through at least September 1970. VIN around 10000.

I can attest to that with personal experience.

My 12/70 car HLS30-17486 does not have the Philips head pedal stop.