as I understand it, these "coins" were NCLT - they were issued at a premium - you paid 3 shillings for a 2-shilling coin, so very few found their way into circulation.
Secondly, the Chinese have been copying these in recent years.
I'm sure there was a thread on CCF about it -that's the only way that I'd know about it.
The copies were pretty obvious when one had a good look at them.
To evaluate the present item, we'd be better off with a pic taken, out of the 2x2, and the coin filling the pic.
A couple of years ago, genuine Centenary florins were $200 ~ 250 on
ebay, but then they nearly doubled (must've been when silver shot up), and most went for about $400. I haven't looked recently.