They might well come with the bootlaoder fitted, but have been probably been programmed to need a crystal\reasonator connected. If that is so you wont be able to use an ISP programmer or the bootloader until there is an external clock source.
They might well come with the bootlaoder fitted, but have been probably been programmed to need a crystal\reasonator connected. If that is so you wont be able to use an ISP programmer or the bootloader until there is an external clock source.