Who knows factory cylinder heads ?

I have a 72 - 360 that is fairly stock with exception of intake, carb and unknown bigger cam. Today, I checked to see if I have adjustable rockers. I also wanted to see how tight or loose my lift rods and rockers were. I haven’t the slightest issue with the engine. No chatter and runs great. I just wanted to look at them. They are matching number 72/360 original heads.
I have no clue if it has sold or hydraulic lifters. But, I believe they are solid based on the rockers or rods won’t budge the smallest amount when pushing either downward, on all 8 I checked.
My understanding is my rockers are not adjustable as there is no adjusting nut on them. I have 3 out of 8 rods or rockers on the passenger side. That have the smallest amount of play and the rods spin very easily. One rod has a considerable amount of up and down play of those 3 that spin easily. Where the other 5 are tight as can be. If these are non adjustable why would this be the case ? And if I do infact have solid lifters can you add adjustable rockers to the stock arm to make them adjustable ?