Late 40's Early 50's., The Information on Rollfast is slim, and comes with the crowd who own them for the most part. You have a deluxe rack on the back, which leads me to think it had a tank at one time. Looking closer, your links arent skiptooth, so Id say early 1950s would be accurate.
The fenders and Badge on Rollfast can be difficult to match up and looking at this variation, its all there and correct. Maybe an aftermarket chainguard, but might just be particularly rust free.
Ladies saddle, looks like Persons or Troxel. The leather covered ones with crash rails are worth a few bucks, even if incorrect. you might be able to trade it here for a slightly less conditioned Male saddle to fit to your rig there.
Awesome Model. Having a '38 and a '63ish., I really enjoy the Rollfast Brand and overall build. Its a sturdy and sound bike. Id say you have 200$ cash sitting there on wheels, as is. IMO
FZ