Personally, I just the parts I needed at West Marine. Well, pawls and springs for sure. Lewmar parts, it seems, are little changed over the years, and are widely available from chandlers and online (e.g. Defender.com). Lewmar themselves, by all accounts, are also very responsive for old winch parts. A friend had a Pearson 26 (smaller winch), and dropped one of the gears overboard (!); Lewmar could still provide a replacement part.
I could have sworn my main winches were '42s. I'll have to have another look next time I'm on board.