cyclechic,
I've always seen bungs covered up with wooden dowels/plugs. Are yours made from decorative metal? I agree that pics would help here. If you can remove one then a local metal worker could cast some replicas for you.

Sorry, this is my first post and it took me a bit to figure out the photo upload procedure. The covers are some sort of silver colored base metal and slightly decorative. I tried to fabricate them using copper but they are pretty primative looking. The bung covers are to cover the bungs or bolts that hold the wood together.

I would look for bed bolt covers

Here is a link that might be useful: bed bolt covers

Even if you find some it will be hard to match the patina of the existing covers. You might consider consolidating all the holes onto 1 side (hidden) or have new ones cast/made with your initials, a word, or family name?

Ohhhh, the bed bolt covers are really nice, they just might work. I had thought about having some made but, didn't know where to go or what to ask for. As far as the patina, I use liver of sulfur as a silver, copper, and brass patina in jewelry making and thought it would work if I had some covers made. You all have been very helpful. Thanks so much.

Horton brasses in the earlier link can probably make them for you. I had them make some wrought iron trunk braces for me a few years back, and they liked them so much they put them in their catalog.

Bung hole covers are also found with rain barrels.
So if you look at wine making, you might find some more. I don't know if they're decorative, but it's worth checking out.

VanDyke's might have something, too.

Did you ever find? I am looking for the same thing

I found these on eBay. Search for bed bolt screw covers... might need to be patient it took me awhile before I found vintage ones for sale. Good luck! I would have shared link but it no longer exist nor the seller.

Look online under knobs. I found them very reasonable and in many different finishes.