Yes you could. Pewters are Pastel Cinnies...no super anything. Here's the breakdown:
6.25% Super Pastel Super Cinnies
6.25% Normals
12.5% Pastels
12.5% Cinnies
25% Pewters
6.25% Super Pastels
6.25% Super Cinnies
12.5% Sterlings
12.5% Super Cinny Pastels
I just looked the names up in NERD's book...it looks like they labeled the Silver Bullet as the Super Pastel Super Cinny and the Silver Streak as the Super Cinny Pastel. Greg Graziani's list has the Silver Streak as a Super Pastel Black Pastel and the Silver Bullet as the Super Cinny Pastel, though, which is how I thought it was. I always mixed up the names before, and now I'm really confused. Hopefully someone will clarify.
Hope this helps,
Shelly