Correct, but you can find Spitfire HF.Mk IXs with Merlin 70s (higher tuned than even the Merlin 61) with clipped wings. It was kind of arbitrary at times, e.g. this is the fighter we have and this is the mission profile it will be used of, clip the wings. LF, F and HF refers to the engine, the wings could be clipped, standard or extended on any of them. In practice only standard and clipped were used with any frequency.