I have a pre-1955 model. Had it rebuilt by Bill romel. He told me that the older models have a thicker reedplate, anmd are worth the rebuild. It now has a lucite comb, because the wood comb was cracked. It is my best sounding chromatic, at least to my ears.
bullfrog
Older harmonicas often had reedplates of aluminium. That's why they are thicker. Aluminium is lighter than brass, and Hohner could save on import tax, which was based on weight for some time. Cheers, Fernando