The document you were looking at says the "Roku 2
HD" has the 600 MHz CPU, it doesn't say "Roku HD". In short, yes you paid $10 more for the newer remote control and a different color scheme. One thing to keep in mind, just because the old CPU was 600 MHz and the current one is 400 MHz doesn't mean that it is 1/3 slower. One is ARM and one is MIPS, two totally different types of architecture - each has their own pros/cons.
If you want you could cancel your order from roku.com and order the "old" LT from amazon
with the newer remote for $51 shipped.