Barred rocks can have light gray/dull colored legs! Sadly, this isn't a breed standard and will be a DQ if showing. I bred a low quality flock for feedstore sales and I got a couple of those. Hatchery chicks I've seen this way too .
However all these chicks have whitish legs, so unless your country has different standards for BR then I doubt these are purebreds.
Also, the barring on the first chick is super unclean, even a female BR has cleaner bars then that chick shown.
So, in theory, they could be purebred BR just lower quality (in form of breed standards anyway)
The best way to determine male from female in BRS (purebreds only), is by the barring. Males will have even bars down most, f not all there feathers. Making them seem evenly white and black. Females are darker. Being more black then white. Females have dark wash down there legs while males have solid yellow legs.
First picture I uploaded is female
Second is male
Good luck!
Edit: you didn't get these guys from the same breeder as the orphingtons?