I don't think so.
Probably they used the Brown Bess for color matching only.
I'm mostly reffering to the actual type of paint than the color of paint. Over at the Tracking Tube Junkyard entry, SD Studios states that the Brown Bess humbrol paint does not hold up well when dry, but the OD lacquer is very sturdy and very durable. I asked why they don't make Brown Bess in lacquer and people said they can't make them.
So if that's the case, I thought maybe the same problems with the Brown Bess paint used on the Pulse Rifle would yield the same results that SD had. Less durable and not meant for use.