If the dealer says it's installing an "updated clutch" and it's taking a couple days to do it, they are probably installing a new set of clutch plates and seals. There does seem to be an upgraded clutch version out there and it would make sense this is what they would put in your car.
As it is a new clutch, the dealer will probably tell you a break-in period of 1,000 miles or so is required before the "green" clutch behaves "normally". In practice this shouldn't be a big deal, but if you notice a few shudders or other odd behavior early-on, don't panic as it may very well go away as miles accumulate.
This is actually good news as the original clutch and seals seem failure-prone.