Nope. The next iPad would most likely not come with anything below iOS 6.2 stock if not iOS 7, meaning there won't be on or have an iOS 6.1.2 tailored for the next new iPad. Plus, if you want to downgrade, you have to take advantage of an exploit. There hasn't been one that's been found yet since the pre-A5 devices, which all use the LimeRa1n exploit, with the iPad 2, which follows a slightly different set of rules if you were to downgrade, which needs several more steps and requirements before you can do so. You need SHSH blobs to downgrade/restore selectively to an iOS, and if the new iPad comes out on iOS 6.1.3, 1, you won't have iOS 6.1.2 tailored for the device, and 2, you won't have the ability to save the SHSH blobs since the iOS doesn't exist for the device