XS1B tachometer

Hi Members, in the process of reproducing a couple of parts out of necessity, the early seat trim I've got the middle recess tool made with the cross section markings as originally done. but having trouble shape forming as a hobbiest, I will post later if anyone's interested.
The main consideration I have is the tachometer chrome body, as you know original production was plastic then chrome finished.
I'm going to sand cast in metal, machine then chrome to look original.
I was considering methods of re-attachment of the original bottom plastic trim, the bottom edge of the casting will have a recessed edge for the flush fitment to the original plastic moulding.
I didn't want to just glue, but was considering inserted chrome grub screws
or such like, not knowing if this would be acceptable to the purist.
Any ideas you may have would be greatly appreciated.

Dunno but thinking 3D print plastic, then chrome? There are folks that chrome plate plastic.......
Caswells has kits to plate plastic.

The problem with 3D printing is you need an original unaltered plastic body to scan.
To get the body separated on the early model tachometer I had to separate by cutting the original body making scanning every difficult without the complete original. If someone has got a tachometer body suitable for scanning I'll pay shipping and return costs to get the job done.

I was planning on using Alsa Chrome paint.