Hello Jim,
Yes, the different style lettering on the side of our slides was used as a "code" for us in the factory for the type of stainless steel used for that particular slide and also for a repositioning of the firing pin location cut into the slides. The original Farmingdales were all made of a top stainless steel called 17-4. Once we moved to Deer Park, and the letting was still "Old English Text", those slides were still made of the 17-4 material. We found out in the early years that with the barrels being made out of 416 stainless steel and the slides out of 17-4, a harder material, we were having issues of premature wearing of the lockup between the barrel and the slides. Speaking with other manufacturers who we got friendly with, we found out that the dissimilar materials were the culprit. We switched to 416 stainless steel for both the slides and the barrels, which significantly reduced the wear, or the rounding off of the barrel lockup area. That improvement greatly helped the lockup and durability of the firearm. The slides that have Deer Park, N.Y. in block letters are the newer design using the 416 stainless for both the slide and the barrels. The last update to the slides would be the slight repositioning of the firing pin about .001" to .002" to line up the firing pin directly in the center of the 9mm round. That was more of Karl being German and, dare I say "anal" about making the pistol as perfect as we could. Those slides with the repositioned firing pin hole are indicated by us changing the "Made in USA" to "Made in U.S.A." when we added the periods in between the letters for USA. There you have the three different slide setups for the duration of our manufacture.
I trust that helps with the mystery of the different style lettering on the side of our slides. It was an easier code than trying to put serial numbers on each and every slide.
Regards,
Eric C. Rohrbaugh
