So going by this your initial 56* was a special order from Ping? If so your serial number would give the specs.

American Golf Supplies are the Australian distributor and have been great to deal with for me every time. I would give them a ring. If your wedges were special order they should be able to give you specs per the serial number and you could also discuss what your chances are of getting a 60* 4.0 made to order. They should be a lot more helpful than the retailers. If you have no chance of getting a 4.0 at least you will know where you stand. The S159's drop in a week or so and omg is that Midnight finish hawt.

https://americangolf.com.au/
Thanks for this. They told me they'd sold all their left over wedges to a golf shop in Sydney so I contacted them but they didn't have any of the 60S left. So I will just get the new model. Wedges wear out more quickly anyway right, so I might upgrade my 56S in a years time too.