In the end, whether you should download the upgrade is up to you. If it was me I would not proceed without a full backup ready so you could recover your system if all goes bad. Make sure you read all the information on this page as it contains important information you should weigh up before proceeding. If this doesn't work, the other option as you've already referenced, is to download the macOS Sierra Patcher Tool for Unsupported Macs. Once you've got a copy you could try installing from the original downloaded location to see what happens. If the App Store allows you to download the upgrade, then you could just download it (without installing it) and then make a copy of the installer.
In fact, a few weeks back I saw this occur on a MacBook Pro (15" Late-2008) model that was running Snow Leopard 10.6.8, even though Apple doesn't officially support upgrading from this hardware or OS.Īs to whether you can install it, the answer is yes, even though this isn't officially supported by Apple. However, for whatever reason, the option to upgrade to macOS Sierra is appearing in the App Store for a whole range of unsupported Macs. Officially your Mac is not supported by macOS Sierra.