All BDA pistols chambered in 9x19mm, .38 Super and 7.65x21mm (this chambering is rare, and for the European market exclusively) have Type 1 slides.
All
serial production BDA pistols chambered in .45 ACP, as well as all Hawes-imported P220 pistols chambered in .45 ACP (listed in the Hawes catalog as the Model 745), have Type 3 slides, as seen in the pics above- beveled edges on the slide rear of the ejection port and 12 slide serrations instead of 19 slide serrations.
With respect to BDA pistols in .45 ACP, I have evidence of at least one pre-production example being produced with a slide that does not fit into any of the five categories I listed on this page.
Notice how we've talked about Type 1 and Type 3 slides. Where's the Type 2? I get the impression these transitional slides appeared only on the P75. At least, that's the only place I've ever seen Type 2 slides.
I looked through my research materials and this is all I have in the way of pics of this slide type. In this pic, you see right and left side views of a P75 with a Type 2 slide. In the slides-only portion of this photo, we see a comparison of Types 1 and 2, with the Type 2 slide on the bottom. Very subtle difference. For commercial production P220 pistols, it appears they went from Type 1 directly to Type 3 slides.
The P75 is much like Walther's postwar P38, in the sense that engineering changes made to these pistols were the same for both the respective commercial examples and for the pistols intended for military use. Any change made to the design or to parts were made across both commercial and military production, so one would be lead to believe that there are commercial P220s out there wearing Type 2 slides, but I've never seen one, at least not that I can recall.