Changing AR stock

I have a friend wanting to change the stock on his AR but his is an older model, I believe A2. I have never worked with an A2 and was just wanting to confirm that the lower is still the same before helping him find parts.
He is wanting to switch from the standard solid stock to a collapsible, am I crazy or is all that is needed is the stock, buffer tube, and castle nut(I believe that's what its called)?
Also the previous owner managed to break the tip off the bolt catch(where it catches on the follower), have these changed any over the years?
Thanks Guys

is all that is needed is the stock, buffer tube, and castle nutReceiver end plate, buffer, and buffer spring as well.

Normally stocks some with everything except the wrench for the castle nut.

Also the previous owner managed to break the tip off the bolt catch(where it catches on the follower), have these changed any over the years?
No. Any replacement part from a reputable manufacturer will work.