There were several changes with the introduction of the Model 39-2 including the feed ramp and moving the slide serrations forward but relocating the PATS PENDING was not one of them. The PAT'S PENDING was originally located on the slide to the
left of the ejection port from s/n 1300 through 60,000. It was then relocated
below the ejection port on Model 39's between s/n 60,000 to 121,000 and stayed that way with the introduction of the Model 39-2 at s/n A121,000 through A580,000 (like the OP's) and then was once again relocated to the
left of the ejection port around s/n A 580,000 until it was eliminated at around s/n A600,000. All the ranges are approximate and variations can be found at either lower or higher numbers.
Serial number range 1300 to 60,000
Serial number range 60,000 to 121,000
Serial number range A580,000-A600,000
Serial number greater than A600,000
