I Want Some Info On My Pvalvs VI Pont. Maximus Coin.

I bought a Pvalvs VI Pont. Maximus coin with a broadstrike error two years back. I wanted to learn a little more about this coin as I don't know if my original source was all that reliable(I don't do much foreign collecting.)
From my research I found that it's supposedly a 5£ commemorative piece for the vatican. It was originally sold for $75-80 to collectors in the early to late seventies. I think the quantities made were ~5000-8000(,again I don't know how realistic my source was,) and are rare outside of Europe. I've seen them for sale for $20-30 and $500, so someone was on something when they did on of those posts, and now I'm a little confused too.
Any info, worth estimates and/or clarifications are very appreciated. Thank you