Silver Monark round - add'l info requested

ZenithBullionPA

Was looking through some of my coins and rounds today. When I ran across this one, it made me wonder about the history of it. Who was responsible for design and manufacture? How many were made, and where? In what year(s)? Etc.

A little Internet sleuthing didn't yield much info. Will post links below.

Here are photos of mine:

I bought this from my local coin shop in March of 2024 as a generic round - same price as any other at the time. Since this one was unique, and vintage, I got this one. I then discovered that they tend to go for a small premium online. I paid checks notes $25 for it, and found online listings at the time for $38.

Here we are two years later, with silver closing at $80/oz on Friday 4/17/26, and these seem to be selling for somewhere in the neighborhood of $100, give or take. So there still seems to be a small premium for this piece. Sold items from eBay: https://www.ebay.com/b/Silver-Monark/39489/bn_7023320011?LH_Sold=1&mag=1

So I'm asking if anyone here has any memory, or sources they can share, with further detail regarding the history of this particular type of round.

Sources:
The most useful one I've found: https://www.agroundworld.com/1-oz-silver-monark-eagle-shield-silver-round-1481.html - This one references the shield paired with a 1974-dated "Silver Bullion Exchange" obverse. I found an example of that version on the APMEX site: https://www.apmex.com/product/249682/1-oz-silver-art-round-silver-bullion-exchange-monark-shield
- Mine doesn't have a date, and it doesn't say "Silver Bullion Exchange" so it's not necessarily from the same manufacturer...or is it? And is it safe to assume Silver Bullion Exchange was the name of a silver bullion manufacturer in the 1970s?

Also: https://en.numista.com/438860

And then I read various pages with a round for sale, but these have little to no information. The best only said "1970s" or "1974" but otherwise no details.