I was going through my buffers to throw together a rifle for something to do. ( realized i need more spare parts   ) I have one buffer that doesnt have a roll pin like the early carbine buffers. have we gone over this yet? I thought all the "modern" rifle buffers had roll pins.

I believe that I read somewhere that some (maybe early ones??) just pressed on

It's been covered.  From member Coldblue who supposedly worked on original A-2 project.

"The pin was added top the M16A2 technical data package as approved for the USMC in 1983. That was shown to keep the buffer assembly together in extreme cold weather. The Army probably was slow (or maybe ignored the change) to change form their M16A1 tech data that supported their vast inventory. And probably vendors were given wavers not to include the pin because quite frankly, the logistic side of the Army was not totally on-board, especially with A2 parts that could retrofit to older A1's"

None of the de-mill 70's kits I purchased have ever had a pinned buffer or in the NIW cage earlier retro era dated buffers I've purchased.  I have seen a few members here with supposedly NIW 1969 date buffers with roll pins but I'm a little suspect on authenticity personally.

I have seen and purchased new out the box of 100 quantity wine colored buffers with roll pin from as current as 2015 production.  Usually 2-3 in every box of 100 and have seen as many as 7 mixed in with the more popular lime colored bumper units.  I generally buy them when I can dig into a new box as they are simply different than most everyone else's today.  Figure rifle buffers aren't the sellers today they once were as carbine, SBR and pistol builds are far more popular in factual numbers.