Complex sentence: A unique "Karmann Hardtop" or "Notchback" 356B model (1961 to 1962) was essentially a cabriolet body with the optional steel cabriolet hardtop welded in place.
Split into simpler sentences: A unique "Karmann Hardtop" or "Notchback" 356B model was produced in 1961 and 1962. The 1961 production run was essentially a cabriolet body with the optional steel cabriolet hardtop welded in place.