Model no. 630 is a modification of model no. 620. The scales have a specific, asymmetrically curved shape. Colloquially, this scale shape is often referred to as a "dogbone". This model seems to have been developed especially for the American market, but is rare overall. Only aluminum or steel with a guilloche finish was used as the scale material.
Due to the special scale shape, most of the tools are visible and accessible when closed, which allows them to be opened easily and is therefore an advantage over the classic No. 620 models.
If you place a model No. 630 interactively over a model No. 620, you can see the difference in scale shape in the image on the left. The scale part colored gray and dashed black is missing from model no. 630. Otherwise the construction and the riveting is identical.
The model no. 630 was produced for a few decades and in small numbers. This particular scale shape disappeared from production a long time ago, but was also temporarily used for model no. 623 (with additional scissors).
The model no. 630 was probably taken out of the product catalog at the beginning of the 1970s and was no longer produced.