Plymouth Rocks come in many colors....barred is the most common, but partridge is what the OP has. I'm not seeing anything screaming rooster at this point...how old are they? You might just need to repost pics in a few weeks.
I got them at tractor supply sign said Plymouth red rocks, thier about 4/5 weeks. Both of the two reds? combs are significantly bigger then the other four birds, and I also read about thier tail feathers pointing downwards usually means boy.
I didnt know the variety of plymoth rocks. When I was researching for my chickens I wanted the barred so I missed other ones. With my barred rock boy at 2 weeks old he was totally different from the pullets. He already had a comb turning red and getting larger than the girls. However I dont know if it is as obvious with other plymoth rock varieties. Also my boy was smaller than the girls with not much tail feathers until about 6 weeks old. Good luck.
My plymoth barred rock boy at 3/4 weeks
Neither one of my plymouths have a red comb but thier combs are are taller then my buffs and ambers. They're yellow just taller. The plymouths are smaller then the rest with only one actually developing tail feathers so far
When I got my 4 plymoth barred rocks I also bought 2 brown leghorns 2 ee's and 2 light brahma's. My 3 pullet plymoths were all a bit smaller than the other breeds with taller combs than the others. The only one with the development of red comb taller than even the plymoth girls was my plymoth boy. If yours are anything like the plymoth barred rock I would think the combs would be showing obvious red comb coloring by now. Time will tell. Sorry I know its not much help. Would love another pick in a couple weeks. Another note. My boy strut around from only 3 weeks old. He acted different than all the other pullets and at 6 weeks he even started keeping the girls in line when they started establishing the pecking order. He would intervene when the girls got to rough. He would simply jump in the middle stop the behavior and strut away. Maybe watch the behavior too.