On all older bikes you can raise and lower the stem, but only if it is not stuck. Stuck stem and seat post are both pretty common on old bikes, particularly those that have been ignored for years (which is the case for most of them).

I love my leather mallet for giving stem bolts a solid tap without damaging their finish. Do not use a hammer, if you do, use a block of wood between the stem bolt and the hammer. Also, do not remove the bolt all the way! You are trying to get a wedge to release that is at the bottom of the bolt. Pull the bolt and there is no way to release the wedge.