Anyone running an Airman AX30U-3?

We have an Airman AX30U-3 (not an AX30UR-3 or AX30-3) that we bought locally several years back, and it is about to need new tracks, among other things. However, this specific model doesn't show up on parts sites. I have two specific questions, at least for now :) .

1. Does anyone know if this model is comparable to a similar model that actually shows up in parts warehouse databases?

1. It currently has hybrid tracks (i.e. metal tracks with bold on rubber pads) with 42 links. If we replace these with rubber tracks will any of the undercarriage have to be replaced or will they just fit? I've heard that some will, some won't.

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