Door / speaker hardwear parts needed

[jgurnari]

Hardware for speaker mounting shown, threaded stems that are anchored inside the door panel that holds the speaker in place

Are these parts available anywhere?

[Dpmulvan]

Try grainger or McMaster Carr they’re called Mountable Threaded Studs.

[EC900]

If all else fails, there’s a 3/4” elevator bolt which is the smallest length, which has a flush head.
Maybe those old ones can be reattached (cleaned, painted, prongs straightened and sharpened) if replacing the door card with new stock, but they look delicate and may not withstand a strike with a mallet, or some JB Weld?
Another suggestion would be a fabrication, using a small speed nut with appropriate sized stud JB a welded in place.

[Callum69]

I appreciate the information and advice you have shared.
My Mercy

[RSTarga]

Thats quite a bit of rust. Do you have the plastic sheet vapor seal in place on the door behind the door panel.Keeps the water off the door panel and a flap should cover the back of the speaker