Ok. Answer is partially yes. If you want to use sd recovery, you neednt. But if you want to use recovery on nand, you should obey this.
I have only relatively recently started to use android on nand, for most of the time my phone has had wp7 in nand and i used sd builds and more recently NativeSD.
Since the advent of NativeSD, and the emergence of excellent sd recoveries, it makes me wonder why anyone would want to use up their precious nand space with a recovery. It is a rarely used commodity on a running rom. Although 5-9Mb of space is not a huge benefit, every little bit helps, especially for tmous users with everything on nand.