As above –
There have been many tiny (and sometime large) design iterations of the Speedmaster over the years. Anything from movement types, to rear engraving, to slight iterations of the bezel, to what materials the printing was done with..
On sapphire vs hesalite – it’s not as simple as sapphire being always more expensive. Hesalite was the original specification used by NASA for the Apollo missions, so carries a lot of prestige within the Speedmaster world as being the original, or closer to it.
I can’t comment on the rest of the watch without a link to the exact watch. Though admittedly my knowledge isn’t great, but there are looooads of vintage Speedie forums/sites out there.
I love my speedy, it’s a really, really cool watch.
It’s worth adding, the ‘Moonwatch’ only comes in a manual wind. There are plenty of Speedmasters that are automatic (and have the awesome Omega co-axial movement if modern) but they are not moonwatches.