My question is can an individual file a for 1 for an SBR.
I have a couple of pistols I would like to get a stamp for.

Sure can, state laws can and will vary however.

Yes, and if you already have a Silencershop account they offer their Form 1 service that makes it real easy. You just enter the firearm info and they populate the forms and pull your prints and photos right from your account. They charge $35 which is basically the price of prints and pictures anyways and the process makes it super easy. Only down side is that its taken about 1 month from paying for the service to having my check cashed by the ATF which is probably a bit longer timeline than doing it all myself.