The only difference between the R and non-R (aka the "E1", I asked the Brammo folks what they called the "non-R" and that's what I was told) is some carbon fiber bits and the suspension.
Specs page says:
ER: Fully Adjustable 43mm Marzocchi Forks
E1: Semi-Adjustable 43mm Marzocchi Forks
The Fully Adjustable forks are "gold", while the Semi-Adjustable are black. So by definition, if the bike has black forks, it's an E1, if they are gold, it's an ER.
I suppose you could take the black forks and put them on the ER, but then you would have an E-Frankenstein!
Heck, if you really wanted black forks, you could trade with somebody who bought an E1. I'm sure many people would trade up for Fully Adjustable forks. Or you could paint your gold forks.