Yes, exactly, and if you use them for the other purpose of compensating for a severely skimmed head you will often get very incorrect rocker geometry, and increased wear, with some loss of performance possible. Using shims under the pillars for that purpose is just plain wrong.
If the head has major skimming, you really do need shorter pushrods, although a cam regrind, plus grinding the tappet faces so the bottom of the tappet was at its minimum acceptable thickness, could possibly help to achieve the same result. A little bit off here and there might add up to what is needed.
This is true on all conventional overhead valve pushrod engines with the camshaft(s) in the block, not just the A series.