Hello Steve,
The reason only a few are offered in wood is that in the early 1900s 32 and 38 top breaks came standard with hard rubber grips. You could order pearl or ivory grips as a special order item. But, wood grips were standard only in 1878 and 1879 on blue 38 Single Action "Baby Russian" revolvers. OK a few wood grips were also used on some of the 38 Safety Hammerless guns after 1935. That's it though, wood just wasn't offered on the 32 and 38 top breaks. The two that are shown in the catalog, the 32/44 and 38/44 Are for the New Model 3 frame. Many of them came standard with wood grips.
The telegraphic codes were largely used by distributers for ordering the guns from S&W. Telegraph rates were expensive so code words were developed for each variation to save letters during the sending of the orders. If you already owned a Smith & Wesson and wanted to upgrade to pearl or ivory you coudn't just send for the grips and slap them on. You had to send the gun back to S&W to have the grips fitted.
cflier

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Mark Connot