Yes: There are at least two types of membrane. The Mitsumi is for the AmigaTech (post-Commodore) keyboard and A2000/A500 keyboard... possibly A1200. The A4000 had a different membrane although I can't recall the manufacturer. I'm sure the Mitsumi won't fit an A600 as it had the smaller keyboard without the numeric keypad. I had just replaced a newer AT keyboard's Mitsumi membrane last winter.
There are various membranes and keyboards across the models, even if I limit it just to Mitsumi manufactured ones.
The A500 appears to have had two Mitsumi versions (A619A and A619B) - one with extra blank keys - we merged these two versions to make one single replacement membrane. This also fits the A4000 model.
The A600 had at least one blue Mitsumi membrane (only part number we know is NWT F-1 8770-0056 REV. E) and two slightly different green Mitsumi membranes (the 5647B appears to be the more common one, with the 56C47A apparently in Australia!). We currently sell the blue one and more common green membrane.
Unfortunately, we only found out about the other green membrane after the production run, so would need to do a specific run for those (at the moment only 3 people have expressed any interest).
Hence the question about the A1200 membranes - at the moment, it appears the A1200 all use the same keyboard membrane (as no-one has stated otherwise)....
