Here is the thread I had referred to. Jaime (Aussie Collector) is one of the most passionate collectors of 41, 41-1 and 46 models and an excellent source of knowledge on the 41/46 models.
Jaime indicates an A suffix means a duplicate serial number. This is likely true, however, I have examined 2 Model 41s with both an A prefix and an A suffix. On both the underside of the barrels were also stamped with the matched number (where they are regularly not numbered from the factory) and service date on the grip frame, visible with stocks removed, indicating a repair.
I have also examined a Model 39 with a A suffix and 2 Model 39-2s with both a A prefix and a A suffix where, again, the underside of the slide is numbered to the gun and service date on grip frame, visible with stocks removed.
Somewhere along the line I read the A suffix could also indicate a warranty repair and / or frame replacement thus trying to on a gun where the serial number does not fit into the standard ranges for that model or models e.g. a Model 39 with a A suffix serial number.
I'm hoping Kevin Williams will share data on serialization of 39 series that had undergone factory repairs and / or frame replacement.
Serial Number